chore: reorganize stake button tests

[amitabh94]

Description

This moves the stake button tests from Tokens test to StakeButton.test.tsx for relevant code ownership.

This also adds a test to navigate to stake screen when on unsupported network.

Related issues

Fixes:

Manual testing steps

1. Go to this page...

Screenshots/Recordings

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 59.84%. Comparing base (faf5340) to head (33c2749).
Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #13017   +/-   ##
=======================================
  Coverage   59.83%   59.84%           
=======================================
  Files        1873     1874    +1     
  Lines       42121    42143   +22     
  Branches     5473     5479    +6     
=======================================
+ Hits        25204    25221   +17     
- Misses      15235    15239    +4     
- Partials     1682     1683    +1     

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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

[Matt561]

LGTM!