…r with safeareaview cp-7.69.1 cp-7.70.0 (#27446)

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## **Description**

Standardizes safe area and header inset behavior across the main tab
views (Wallet, Explore, Activity, Rewards).

1. **Reason for the change:** These views used `edges={{ bottom:
'additive' }}` on `SafeAreaView` and `includesTopInset` on headers,
which was inconsistent with the desired layout and could cause double
insets or incorrect safe area handling.
2. **Improvement:** Switched to `edges={{ top: 'additive' }}` on
`SafeAreaView` and removed `includesTopInset` from header components so
the top safe area is handled by the screen container and headers align
consistently.

## **Changelog**

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## **Related issues**

Fixes: #27443 

## **Manual testing steps**

```gherkin
Feature: Safe area and header insets on main tabs

  Scenario: Wallet, Explore, Activity, and Rewards use consistent safe area
    Given the app is open on a device or simulator with a notch/safe area

    When the user switches to each main tab (Wallet, Explore, Activity, Rewards)
    Then the top safe area is applied by the screen (no double inset)
    And the header (title + accessories) aligns correctly below the safe area
    And the bottom of each view respects the tab bar / device safe area as before
```

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**


https://github.com/user-attachments/assets/0eda5978-7bd5-4428-86ea-f62637fb06ed


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

### **After**


https://github.com/user-attachments/assets/a8ff8e19-a49e-41f4-9056-7c2271da8c66


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

## **Pre-merge author checklist**

- [x] 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
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Layout-only changes to core tab screens
(Wallet/Explore/Activity/Rewards) that can affect safe-area padding and
scroll behavior across devices, plus removal of Wallet’s bottom
fade/scroll tracking logic which could subtly change UX on the homepage.
> 
> **Overview**
> Standardizes safe-area handling across the main tab views by switching
root `SafeAreaView` usage from `edges={{ bottom: 'additive' }}` to
`edges={{ top: 'additive' }}` and removing header `includesTopInset` so
the top inset is applied consistently by the screen container.
> 
> In `Wallet`, removes the bottom fade `LinearGradient` overlay and its
associated scroll/size tracking state, simplifying scroll handling to
just notify homepage section subscribers via `handleHomepageScroll`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
c4b0e41. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->