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
for (int l = 0; l < count; l++) {
			glTexImage2D(GL_TEXTURE_2D, l, rt->color_internal_format, width, height, 0, rt->color_format, rt->color_type, nullptr);
			width = MAX(1, (width / 2));
			height = MAX(1, (height / 2));
		}
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, count - 1);
		glGenFramebuffers(1, &rt->backbuffer_fbo);
		glBindFramebuffer(GL_FRAMEBUFFER, rt->backbuffer_fbo);
		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rt->backbuffer, 0);
		GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
		if (status != GL_FRAMEBUFFER_COMPLETE) {
			WARN_PRINT_ONCE("Cannot allocate mipmaps for canvas screen blur. Status: " + get_framebuffer_error(status));
			glBindFramebuffer(GL_FRAMEBUFFER, system_fbo);
			return;
		}
		
		for (int j = 0; j < count; j++) {
			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rt->backbuffer, j);
			glClearColor(1.0, 0.0, 1.0, 1.0);
			glClear(GL_COLOR_BUFFER_BIT);
		}
		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, rt->backbuffer, 0);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	}
}
void TextureStorage::_clear_render_target(RenderTarget *rt) {