fix: removes addSubjectMetadata and improves Snaps Execution Environment Webview origin restriction.

[Jonathansoufer]

Description

This PR address removal of subjectMetadata in favor of SnapController triggering addSubjectMetadata itself now, and adding a more restrictive originWhiteList on Snaps Execution Environment Webview.

Related issues

Fixes: Comments on the closed PR 8700

Manual testing steps

1. Go to Explore and Install any snap.

Screenshots/Recordings

After

Screen.Recording.2024-02-27.at.15.10.34.mov

Pre-merge author checklist

• I’ve followed MetaMask Coding Standards.
• I've clearly explained what problem this PR is solving and how it is solved.
• I've linked related issues
• I've included manual testing steps
• I've included screenshots/recordings if applicable
• 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.
• I’ve properly set the pull request status:
  • In case it's not yet "ready for review", I've set it to "draft".
  • In case it's "ready for review", I've changed it from "draft" to "non-draft".

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 41.42%. Comparing base (01c6724) to head (14f70e0).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8751      +/-   ##
==========================================
+ Coverage   41.38%   41.42%   +0.03%     
==========================================
  Files        1266     1270       +4     
  Lines       30768    30819      +51     
  Branches     3028     3041      +13     
==========================================
+ Hits        12733    12766      +33     
- Misses      17275    17290      +15     
- Partials      760      763       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[NicolasMassart]

Looks good to me.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud