avcodec/vvcdec: skip inter prediction for IBC blocks

Intra Block Copy relies on reconstructed pixels from the current frame.
We skip IBC during the inter prediction stage and handle it during the reconstruction stage.

libavcodec/vvc/vvc_inter.c

@@ -893,7 +893,7 @@ static void predict_inter(VVCLocalContext *lc)
 
 static int has_inter_luma(const CodingUnit *cu)
 {
-    return cu->pred_mode != MODE_INTRA && cu->pred_mode != MODE_PLT && cu->tree_type != DUAL_TREE_CHROMA;
+    return (cu->pred_mode == MODE_INTER || cu->pred_mode == MODE_SKIP) && cu->tree_type != DUAL_TREE_CHROMA;
 }
 
 int ff_vvc_predict_inter(VVCLocalContext *lc, const int rs)