fix: function to convert personal message hex to text

[jpuri]

Description

Fix function to convert personal message hex to text

Related issues

Fixes: https://github.com/MetaMask/metamask-extension/issues/23282

Manual testing steps

1. Submit a personal sign with message Sign in to VVVVVVV early access.
2. It should show message correctly

Screenshots/Recordings

Pre-merge author checklist

• [X] I’ve followed MetaMask Coding Standards.
• [X] I've completed the PR template to the best of my ability
• [X] I’ve included tests if applicable
• [ ] I’ve documented my code using JSDoc format if applicable
• [X] 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[bot]]

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.

[jpuri]

Closing this PR as we need to support hashes as personal sing text, and the scenario detailed in the issue is more an edge case.