CI Mac: fail if SDK_NONFREE_PATH but no delta SDK

Co not continue if SDK_NONFREE_PATH is set but deltacast
SDK not present there. At this time, this will fail later in
.github/scripts/install-common-deps.sh, anyways. Also the DELTACAST
SDK remains the last non-free SDK so it doesn't make sense to define
SDK_NONFREE_PATH GH variable while not having that SDK.

Author: MartinPulec

.github/workflows/ccpp.yml

@@ -180,7 +180,7 @@ jobs:
         rm -rf ${{ env.SDK_NONFREE_PATH }}
         mkdir -p ${{ env.SDK_NONFREE_PATH }}
         cd ${{ env.SDK_NONFREE_PATH }}
-        curl -S -f -O "$SDK_URL/$DELTA_MAC_ARCHIVE" || true
+        curl -S -f -O "$SDK_URL/$DELTA_MAC_ARCHIVE"
     - name: Run actions/cache for XIMEA
       id: cache-macos-ximea
       uses: actions/cache@main