This PR bumps @metamask/tron-wallet-snap from `^1.25.3` to `^1.25.6`.

The main purpose of this update is to pull in the latest Tron snap
validation fixes, in particular a mechanism to refresh stale or invalid
`expiration`, `ref_block_bytes` and `ref_block_hash` before signing in
both send/broadcast paths.

Preview package:
- `@metamask-previews/tron-wallet-snap@1.25.3-preview-995ddc5`

Release:
- `@metamask-previews/tron-wallet-snap@^1.25.6`

Upstream PR:
- MetaMask/snap-tron-wallet#305

CHANGELOG entry: bump the `@metamask/tron-wallet-snap` to `^1.25.6`

n/a

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

<!-- [screenshots/recordings] -->

<!-- [screenshots/recordings] -->

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- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [X] I've completed the PR template to the best of my ability
- [X] I've included tests if applicable
- [ ] I've documented my code using [JSDoc](https://jsdoc.app/) format
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- [X] I've applied the right labels on the PR (see [labeling
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Not required for external contributors.

- [ ] I've tested on Android
  - Ideally on a mid-range device; emulator is acceptable
- [ ] I've tested with a power user scenario
- Use these [power-user
SRPs](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/edit-v2/401401446401?draftShareId=9d77e1e1-4bdc-4be1-9ebb-ccd916988d93)
to import wallets with many accounts and tokens
- [ ] I've instrumented key operations with Sentry traces for production
performance metrics
- See [`trace()`](/app/util/trace.ts) for usage and
[`addToken`](/app/components/Views/AddAsset/components/AddCustomToken/AddCustomToken.tsx#L274)
for an example

For performance guidelines and tooling, see the [Performance
Guide](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/400085549067/Performance+Guide+for+Engineers).

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- [ ] I've manually tested the PR (e.g. pull and build branch, run the
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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Touches Tron signing and broadcast behavior via the wallet snap; scope
is limited to a patch dependency bump with no local code edits, but
failed or incorrect ref-block handling could still affect Tron sends.
>
> **Overview**
> Bumps **`@metamask/tron-wallet-snap`** from `^1.25.3` to `^1.25.6` in
`package.json` and `yarn.lock`, with an **Unreleased** changelog entry.
There are **no application source changes** in this repo—the mobile app
picks up upstream snap behavior from the new package version.
>
> Per the PR intent, **1.25.6** brings Tron transaction validation
fixes, notably **refreshing stale or invalid `expiration`,
`ref_block_bytes`, and `ref_block_hash` before signing** on send and
broadcast paths.
>
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
b958d77. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: gabrieledm <gabriele.delmonte@proton.me>
Co-authored-by: Gabriele Del Monte <37625739+gabrieledm@users.noreply.github.com>