Normal maps don't affect ReflectionProbes in GLES2

[Firepal]

Godot version:
3.2.3

OS/device including version:
Windows 10 RTX2060

Issue description:
Using a SpatialMaterial with a normal map doesn't perturb a ReflectionProbe reflection,
but it does perturb a WorldEnvironment background reflection.
(The quad on the left is reflecting a checkerboard quad out of view)

AFAIK this behavior is undocumented, so I assume it's not a shader optimization?

Steps to reproduce:

1. Create any mesh with a SpatialMaterial and give it a normal map
2. Place a ReflectionProbe into the scene
3. Move that mesh into the ReflectionProbe

The mesh will use the mesh's unperturbed normals for sampling the ReflectionProbe.

Minimal reproduction project:
normalMapReflection.zip

[clayjohn]

My guess is that this will be fixed by changing this line (and the equivalent for reflection probes 2) to "normal" instead of "normal_interp"

godot/drivers/gles2/shaders/scene.glsl

Line 1603 in 17eb869

normal_interp, vertex_interp, refprobe1_local_matrix,

Normal is the normal with normalmaps applied. While normal_interp comes straight from the vertex function.

[Firepal]

@clayjohn What a very educated guess! :)

[akien-mga]

Fixed by #43885.