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
glBindFramebuffer(GL_FRAMEBUFFER, temp_fb);
	
	CanvasSdfShaderGLES3::ShaderVariant variant = shrink ? CanvasSdfShaderGLES3::MODE_LOAD_SHRINK : CanvasSdfShaderGLES3::MODE_LOAD;
	bool 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, 0, sdf_shader.shader_version, variant);
	sdf_shader.shader.version_set_uniform(CanvasSdfShaderGLES3::SHIFT, shift, sdf_shader.shader_version, variant);
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, rt->sdf_texture_write);
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rt->sdf_texture_process[0], 0);
	glViewport(0, 0, size.width, size.height);
	glEnable(GL_SCISSOR_TEST);
	glScissor(0, 0, size.width, size.height);
	copy_effects->draw_screen_triangle();
	
	int stride = nearest_power_of_2_templated(MAX(size.width, size.height) / 2);
	variant = CanvasSdfShaderGLES3::MODE_PROCESS;
	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);
	bool swap = false;