fix: rive readme

[infiniteflower]

Description

This PR fixes the Rive section of the Animation README and adds info on what devs should get from designers.

Changelog

CHANGELOG entry: null

Related issues

Fixes: n/a

Manual testing steps

n/a

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

n/a

Before

After

Pre-merge author checklist

• I’ve followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). 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.

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.42%. Comparing base (57e5e62) to head (df9d1ac).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #19679      +/-   ##
==========================================
+ Coverage   76.34%   76.42%   +0.08%     
==========================================
  Files        3246     3256      +10     
  Lines       77753    77941     +188     
  Branches    13960    13999      +39     
==========================================
+ Hits        59363    59569     +206     
+ Misses      14531    14509      -22     
- Partials     3859     3863       +4     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud