Fix example not changing popup when mouse moves to another overlapping feature

[matths]

This PR fixes this issue #5327
The documentation example Display a popup on hover.
The Popup doesn't change when moving to another overlapping feature. This is caused by the mouseenter event not triggered again because we didn't leave the layer while moving to the other feature.
As a fix we are using mousemove instead of mouseenter event and check if the mouse is over another feature and the popup content needs to change.

Launch Checklist

• Confirm your changes do not include backports from Mapbox projects (unless with compliant license) - if you are not sure about this, please ask!
• Briefly describe the changes in this PR.
• Link to related issues.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality.
• Document any changes to public APIs.
• Post benchmark scores.
• Add an entry to CHANGELOG.md under the ## main section.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.94%. Comparing base (bedcb86) to head (1290c3b).
Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5442   +/-   ##
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  Coverage   91.94%   91.94%           
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  Files         282      282           
  Lines       39039    39039           
  Branches     6849     6848    -1     
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  Hits        35896    35896           
  Misses       3016     3016           
  Partials      127      127           

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[HarelM]

Thanks for taking the time to fix this example!
I've added a few minor comments.

[HarelM]

THANKS!