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
const RenderTarget *rt = render_target_owner.get_or_null(p_render_target);
	ERR_FAIL_COND_V(!rt, Rect2i());
	return _render_target_get_sdf_rect(rt);
}
void TextureStorage::render_target_mark_sdf_enabled(RID p_render_target, bool p_enabled) {
	RenderTarget *rt = render_target_owner.get_or_null(p_render_target);
	ERR_FAIL_COND(!rt);
	rt->sdf_enabled = p_enabled;
}
bool TextureStorage::render_target_is_sdf_enabled(RID p_render_target) const {
	const RenderTarget *rt = render_target_owner.get_or_null(p_render_target);
	ERR_FAIL_COND_V(!rt, false);
	return rt->sdf_enabled;
}
GLuint TextureStorage::render_target_get_sdf_texture(RID p_render_target) {
	RenderTarget *rt = render_target_owner.get_or_null(p_render_target);
	ERR_FAIL_COND_V(!rt, 0);
	if (rt->sdf_texture_read == 0) {
		Texture *texture = texture_owner.get_or_null(default_gl_textures[DEFAULT_GL_TEXTURE_BLACK]);
		return texture->tex_id;
	}
	return rt->sdf_texture_read;
}
void TextureStorage::_render_target_allocate_sdf(RenderTarget *rt) {