Allow overriding SymbolLayer's paint properties using format expression options

[alexshalamov]

Port of mapbox/mapbox-gl-native#14062

Launch Checklist

• briefly describe the changes in this PR
• write tests for all new functionality. Render tests (Add render test for format expression nested under decision expression #8093, Add render tests for "format" expression's text-color option #8046)
• document any changes to public APIs
• post benchmark scores
• manually test the debug page

[alexshalamov]

Benchmark results:

[ansis]

It looks like a SymbolStyleLayer can exist either with overrides applied or not. And since the state depends on this method call it is hard to tell elsewhere what the state of the style layer is. Your current implementation looks correct but I think someone less familiar with this could easily make changes that either result in setPaintOverrides() being called more or less than once, or before recalculate().

Would triggering it in styleLayer.recalculate(...) make sense?

[ansis]

I think at this point sections is set to the sections of a single formatted expression. In the case where there is a ZoomConstantExpression with multiple possible formatted expressions it will only hold the last one. If the last expression has no overrides but an earlier one does, does this return the wrong value?

For example:

["case",
    ["get", "colourful"], ["format", "red text", { "text-color": "red" }],
    ["format", "default text", {}]]

[ansis]

Would it be possible to make the type of overrides more specific?