[fix](pipeline) if pr addded files, also need run regresion (#23332)

Co-authored-by: stephen <hello-stephen@qq.com>

regression-test/pipeline/common/check-pr-if-need-run-build.sh

@@ -81,6 +81,7 @@ https://github.com/apache/doris/pull/${PULL_NUMBER}/files all change files:
 }
 
 _only_modified_regression_conf() {
+    if [[ ${#added_files[@]} -gt 0 ]]; then echo "Not only modified regression conf, find added files" && return 1; fi
     for f in ${modified_files}; do
         if [[ "${f}" == "regression-test/pipeline/p0/conf/regression-conf.groovy" ]] ||
             [[ "${f}" == "regression-test/pipeline/p1/conf/regression-conf.groovy" ]]; then