Correct feature state id type to number

[bfrengley]

Currently, string feature ids are not propagated through the transformation from GeoJSON to vector tiles (#2716, #6960) and are not supported by vector tiles at all. However, setFeatureState / getFeatureState indicate that they require string ids.

This pull request updates setFeatureState / getFeatureState to require unsigned numeric ids.

• briefly describe the changes in this PR
• document any changes to public APIs

[mourner]

I was wondering the same thing! @asheemmamoowala any objections?

[asheemmamoowala]

@bfrengley Thank you for submitting this PR! Just one small change to the allowed input types for Map#setFeatureState.

[asheemmamoowala]

I think Map#setFeatureState should still accept string types that can be coerced to integers. This would allow what is otherwise a valid id for a GeoJSON feature to be input to the API without explicit conversion.

Based on #4581:

mapbox-gl-js/src/source/geojson_wrapper.js

Lines 38 to 46 in 3b0a1a9

	// If the feature has a top-level `id` property, copy it over, but only
	// if it can be coerced to an integer, because this wrapper is used for
	// serializing geojson feature data into vector tile PBF data, and the
	// vector tile spec only supports integer values for feature ids --
	// allowing non-integer values here results in a non-compliant PBF
	// that causes an exception when it is parsed with vector-tile-js
	if ('id' in feature && !isNaN(feature.id)) {
	this.id = parseInt(feature.id, 10);
	}

[bfrengley]

While I am making this change: is there a reason Map#getFeatureState does not do the same validation of feature.id that is done in Map#setFeatureState? I see #6959 only addresses requiring an id in Map#setFeatureState

[asheemmamoowala]

@bfrengley that seems like a fix worth putting in as well. Thank you!

[mourner]

Rebasing the commits of this branch on top of the base branch cannot be performed automatically due to conflicts encountered while reapplying the individual commits from the head branch.

@bfrengley can you please rebase on top of master for clean merging?

[bfrengley]

@mourner done.