mtmd: enable non-causal vision for gemma 4 unified

tools/mtmd/mtmd.cpp

@@ -1149,6 +1149,7 @@ bool mtmd_decode_use_non_causal(const mtmd_context * ctx, const mtmd_input_chunk
     switch (proj_type) {
         case PROJECTOR_TYPE_GEMMA3:
         case PROJECTOR_TYPE_GEMMA4V:
+        case PROJECTOR_TYPE_GEMMA4UV:
             return true;
         default:
             return false;