chore: fix regex to exclude test files (#1297)

Author: Neenu1995

docker/owlbot/java/bin/format_source.sh

@@ -25,7 +25,7 @@ do
   if [[ $file =~ .*/samples/snippets/src/main/java/com/example/firestore/Quickstart.java ]];
   then
     echo "File skipped formatting: $file"
-  elif [[ $file =~ .*/samples/snippets/src/main/java/com/example/spanner/.*.java ]];
+  elif [[ $file =~ .*/samples/snippets/src/.*/java/com/example/spanner/.*.java ]];
   then
     echo "File skipped formatting: $file"
   else