fix: Unnecessary Account Tracker state update

[tommasini]

Explanation

Unnecessary state update when the balance did not change at account tracker controller polling mechanism, which was causing unnecessary re renders

References

Changelog

@metamask/assets-controllers

• <CHANGED>: Only updated the state if the balance changes
• <CATEGORY>: Your change here

Checklist

• [ ] I've updated the test suite for new or updated code as appropriate
• [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• [ ] I've highlighted breaking changes using the "BREAKING" category above as appropriate
• [ ] I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes