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
while (stride > 0) {
		glBindTexture(GL_TEXTURE_2D, 0);
		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rt->sdf_texture_process[swap ? 0 : 1], 0);
		glBindTexture(GL_TEXTURE_2D, rt->sdf_texture_process[swap ? 1 : 0]);
		sdf_shader.shader.version_set_uniform(CanvasSdfShaderGLES3::STRIDE, stride, sdf_shader.shader_version, variant);
		copy_effects->draw_screen_triangle();
		stride /= 2;
		swap = !swap;
	}
	
	variant = shrink ? CanvasSdfShaderGLES3::MODE_STORE_SHRINK : CanvasSdfShaderGLES3::MODE_STORE;
	success = sdf_shader.shader.version_bind_shader(sdf_shader.shader_version, variant);
	if (!success) {
		return;
	}
	sdf_shader.shader.version_set_uniform(CanvasSdfShaderGLES3::BASE_SIZE, r.size, sdf_shader.shader_version, variant);
	sdf_shader.shader.version_set_uniform(CanvasSdfShaderGLES3::SIZE, size, sdf_shader.shader_version, variant);
	sdf_shader.shader.version_set_uniform(CanvasSdfShaderGLES3::STRIDE, stride, sdf_shader.shader_version, variant);
	sdf_shader.shader.version_set_uniform(CanvasSdfShaderGLES3::SHIFT, shift, sdf_shader.shader_version, variant);
	glBindTexture(GL_TEXTURE_2D, 0);
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rt->sdf_texture_read, 0);
	glBindTexture(GL_TEXTURE_2D, rt->sdf_texture_process[swap ? 1 : 0]);
	copy_effects->draw_screen_triangle();
	glBindTexture(GL_TEXTURE_2D, 0);
	glBindFramebuffer(GL_FRAMEBUFFER, system_fbo);
	glDeleteFramebuffers(1, &temp_fb);
	glDisable(GL_SCISSOR_TEST);
}
void TextureStorage::render_target_copy_to_back_buffer(RID p_render_target, const Rect2i &p_region, bool p_gen_mipmaps) {