Snap marker to pixel if it's lngLat is unchanged

[C2thehris]

Signed-off-by: C2thehris chriskreat@hotmail.com

Closes #13351

Verified markers no longer move after change:
https://github.com/user-attachments/assets/c8cd94a1-6db0-4b09-862b-21ac6120b0fa

Launch Checklist

• Make sure the PR title is descriptive and preferably reflects the change from the user's perspective.
• Add additional detail and context in the PR description (with screenshots/videos if there are visual changes).
• Manually test the debug page.
• Write tests for all new functionality and make sure the CI checks pass.
• Document any changes to public APIs.
• Post benchmark scores if the change could affect performance.
• Tag @mapbox/map-design-team @mapbox/static-apis if this PR includes style spec API or visual changes.
• Tag @mapbox/gl-native if this PR includes shader changes or needs a native port.