When using 3D Terrain raster layers with an id starting with a NUMBER forces the layer order to the bottom

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**mapbox-gl-js version**: 3.3.0

**browser**: android mobile webview / Chrome

### Steps to Trigger Behavior

1.Use Mapbox Terrain-DEM v1
2.Add an initial raster layer that should be on the bottom with an id starting with a string id:"A5000". Then add another layer that should appear on top with an id that begins with a number ie id: "5001"
3.The second layer that should have been on top is now underneath the layer id:"A5000".
4. mapbox.setTerrain(null); will correct the layering problem

### Link to Demonstration

### Expected Behavior
Layers with id's that begin with a NUMBER should respect layer ordering when using 3D Terrian.

### Actual Behavior
Layers with id's that begin with a number are pushed to the bottom of the layer ordering in 3D Terrain mode.

Reproduce the behavior with Mapbox Terrain-DEM v1 using one layer id beginning with a letter and another beginning with a number, then compare ordering before and after mapbox.setTerrain(null). Trace the 3D Terrain layer-ordering path and verify that numeric-prefixed layer IDs preserve their requested order without requiring the terrain reset.

Written by the indexing model from the issue text.