[core] Add DDS support for {text,icon}-size (#8593)

* Update gl-js and generate style code

* Factor out packUint8Pair() helper function

* Draft implementation of DDS for {text,icon}-size

Ports https://github.com/mapbox/mapbox-gl-js/pull/4455

* Fix text-size/composite-function-line-placement test

* Refactor to PaintPropertyBinders-like strategy

* Dedupe gl::Program construction

* Use exponential function base for interpolation

* Dedupe coveringZoomStops method

* Fixup tests

* Fix CI errors (hidden within #if block)

test/tile/vector_tile.test.cpp

@@ -64,7 +64,7 @@ TEST(VectorTile, Issue7615) {
         std::map<
             std::string,
             std::pair<style::IconPaintProperties::Evaluated, style::TextPaintProperties::Evaluated>>(),
-        0.0f, false, false);
+        16.0f, 1.0f, 0.0f, false, false);
     
     // Simulate placement of a symbol layer.
     tile.onPlacement(GeometryTile::PlacementResult {