PlayAnim: use the same GPU backend as Blender

Since the animation player doesn't read the user preferences,
pass the GPU backend as an argument.

scripts/startup/bl_operators/screen_play_rendered_anim.py

@@ -140,6 +140,15 @@ class PlayRenderedAnim(Operator):
             frame_start = scene.frame_start
             frame_end = scene.frame_end
         if preset == 'INTERNAL':
+            # Use the current GPU backend for the player.
+            import gpu
+            gpu_backend = gpu.platform.backend_type_get()
+            if gpu_backend not in {'NONE', 'UNKNOWN'}:
+                cmd.extend([
+                    "--gpu-backend", gpu_backend.lower(),
+                ])
+            del gpu, gpu_backend
+
             opts = [
                 "-a",
                 "-f", str(rd.fps), str(rd.fps_base),