fix(docker): exclude install dir from LICENSE find and use IFS= read -r

Prevent find from re-discovering already-copied license files in the
install destination, and handle paths with spaces correctly.

Signed-off-by: Jack Luar <jluar@precisioninno.com>

Author: luarss

docker/Dockerfile.builder

@@ -51,7 +51,8 @@ EOF
 RUN find /OpenROAD-flow-scripts/tools \( -name "*LICENSE*" -o -name "*LICENSES*" \) \
     | grep -v '/OpenROAD/src/sta/' \
     | grep -v '/AutoTuner/' \
-    | while read -r f; do \
+    | grep -v '^/OpenROAD-flow-scripts/tools/install/' \
+    | while IFS= read -r f; do \
         rel="${f#/OpenROAD-flow-scripts/tools/}"; \
         mkdir -p "/OpenROAD-flow-scripts/tools/install/licenses/$(dirname "$rel")"; \
         cp -r "$f" "/OpenROAD-flow-scripts/tools/install/licenses/$rel"; \