chore: updated celo logo

[viral-sangani]

Description

This PR updates the Celo network icon from a transparent black logo to one featuring a yellow background for improved recognizability.

Related issues

Fixes:

Manual testing steps

1. Go to this select network button
2. Select Celo Network
3. Celo Network should have logo with yellow background (better accessibility)

Screenshots/Recordings

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension 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.

[viral-sangani]

I have read the CLA Document and I hereby sign the CLA