Regression from #71248:

I believe this pull may have caused errors on WebGL since it moves the `GLES_OVER_GL` guard. WebGL does not support texture swizzling per: https://registry.khronos.org/webgl/specs/latest/2.0/#5.19
so this is causing the following trace in Chrome:
```
WebGL: INVALID_ENUM: texParameter: invalid parameter name
```
and it quickly fills up the 256 log limit for the same message in WebGL.

This doesn't appear to be breaking anything asides from causing the numerous log messages.

_Originally posted by @jnlopar in https://github.com/godotengine/godot/issues/71248#issuecomment-1384768973_

CC @rsjtdrjgfuzkfg @clayjohn
case Image::FORMAT_ETC2_RA_AS_RG:
		case Image::FORMAT_DXT5_RA_AS_RG: {
			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_R, GL_RED);
			if (texture->format == real_format) {
				
				glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_G, GL_ALPHA);
			} else {
				
				glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_G, GL_GREEN);
			}
			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_B, GL_ZERO);
			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_A, GL_ONE);
		} break;
		default: {
			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_R, GL_RED);
			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_G, GL_GREEN);
			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_B, GL_BLUE);
			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_A, GL_ALPHA);
		} break;
	}
	int mipmaps = img->has_mipmaps() ? img->get_mipmap_count() + 1 : 1;
	int w = img->get_width();
	int h = img->get_height();
	int tsize = 0;
	for (int i = 0; i < mipmaps; i++) {
		int size, ofs;
		img->get_mipmap_offset_and_size(i, ofs, size);
		if (compressed) {
			glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
			int bw = w;