…fic assets (#187857)

This pull request is created by [automatic cherry pick workflow](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md#automatically-creates-a-cherry-pick-request)
Please fill in the form below, and a flutter domain expert will evaluate this cherry pick request.

### Issue Link:
#186738

### Impact Description:
Starting in Flutter 3.44, building a flavored app (Android/iOS) emits a noisy warning for every single asset file that is skipped because it belongs to a different flavor. For projects with many flavor-specific assets, this floods the build console with hundreds of non-actionable warnings, cluttering the build output and making it harder to see real warnings or errors.

### Changelog Description:
[flutter/186738] Demote flavor/platform asset skipping messages from warning to trace level to reduce build log noise.

### Workaround:
None, other than ignoring the warnings in the build output.

### Risk:
What is the risk level of this cherry-pick?

### Test Coverage:
Are you confident that your fix is well-tested by automated tests?

### Validation Steps:
1. Declare multi-flavor asset directories in `pubspec.yaml`.
2. Place files inside these directories.
3. Build a single flavor (e.g., `flutter build apk --flavor <flavor>`).
4. Verify that the console does not output "Skipping assets entry..." warnings for non-active flavors at default verbosity.
5. Verify that these messages still appear when running with verbose logging (`-v`).

…p all objects that it holds including the sync fence (#187403)

TextureGLES owns a texture and may be given ownership of cached FBO and sync fence objects. Use UniqueHandleGLES to manage the lifecycle of these objects.

Fixes #186899

### Issue Link:

#186899

### Impact Description:

This can cause a resource leak in some scenarios (particularly animated images).

### Changelog Description:

The PR ensures that a GLES fence sync object held by a texture will be deleted if the texture is destructed before the fence was used.

### Workaround:

No workaround.

### Risk:

What is the risk level of this cherry-pick?

### Test Coverage:

Are you confident that your fix is well-tested by automated tests?

### Validation Steps:

Run the sample app in #186899 (comment) using Impeller/GLES.

Look at the count of file descriptors in `/proc/[pid]/fd` for the app process.  Without the fix, the count will increase quickly.  With the fix, the count will be stable.

The exact behavior of the resource leak may vary across devices, and some devices may not show it as a leak of file descriptors.  I was able to reproduce the file descriptor leak on a Pixel 3 with an Adreno GPU.

…shes (#187864)

This pull request is created by [automatic cherry pick workflow](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md#automatically-creates-a-cherry-pick-request)
Please fill in the form below, and a flutter domain expert will evaluate this cherry pick request.

### Issue Link:
#186953

### Impact Description:
During concurrent target builds using SwiftPM, multiple processes might try to create or clean up plugin symlinks at the same time, leading to crashes (e.g., due to file already existing or being deleted while being accessed).

### Changelog Description:
[flutter/186953] When building concurrently with SwiftPM [on macOS/iOS], fix crashes caused by concurrent directory/file/symlink creation.

### Workaround:
Avoid concurrent builds, or disable SwiftPM if possible.

### Risk:
What is the risk level of this cherry-pick?

### Test Coverage:
Are you confident that your fix is well-tested by automated tests?

### Validation Steps:
Run concurrent builds of a project using SwiftPM and verify that it no longer crashes during symlink creation.

…r when parsing malformed fdAT chunks (#188038)

### Issue Link:

#183179

### Impact Description:

Potential crash when rendering animated PNG images.

### Changelog Description:

Fixes an issue that can cause crashes when rendering animated PNG images.

### Workaround:
Is there a workaround for this issue?

No

### Risk:
What is the risk level of this cherry-pick?

### Test Coverage:
Are you confident that your fix is well-tested by automated tests?

### Validation Steps:

Run the unit tests (`./ui_unittests --gtest_filter=APNGImageGeneratorTest.*`)

If this change needs to override an active code freeze, provide a comment explaining why. The code freeze workflow can be overridden by code reviewers. See pinned issues for any active code freezes with guidance.

**Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.

Updates the engine.version file from `77e2e94772b6eb43759e34ed1ad7da4674e19cab` to `a4ce257c68517c1410f4b48ac9852ab5642a3f8d`.