[8.15] [CI] Add suggestion from #189316 (#189765) (#189824)

# Backport

This will backport the following commits from `main` to `8.15`:
- [[CI] Add suggestion from #189316
(#189765)](#189765)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Brad
White","email":"Ikuni17@users.noreply.github.com"},"sourceCommit":{"committedDate":"2024-08-02T16:35:56Z","message":"[CI]
Add suggestion from #189316 (#189765)\n\n## Summary\r\n\r\nThis was just
a suggested change from #189316 which didn't get addressed\r\nbecause of
auto
merge.","sha":"f941ba4d6b60cee41c418140e21b677ca0972c71","branchLabelMapping":{"^v8.16.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["Team:Operations","release_note:skip","backport:all-open","v8.16.0"],"title":"[CI]
Add suggestion from
#189316","number":189765,"url":"https://github.com/elastic/kibana/pull/189765","mergeCommit":{"message":"[CI]
Add suggestion from #189316 (#189765)\n\n## Summary\r\n\r\nThis was just
a suggested change from #189316 which didn't get addressed\r\nbecause of
auto
merge.","sha":"f941ba4d6b60cee41c418140e21b677ca0972c71"}},"sourceBranch":"main","suggestedTargetBranches":[],"targetPullRequestStates":[{"branch":"main","label":"v8.16.0","branchLabelMappingKey":"^v8.16.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/189765","number":189765,"mergeCommit":{"message":"[CI]
Add suggestion from #189316 (#189765)\n\n## Summary\r\n\r\nThis was just
a suggested change from #189316 which didn't get addressed\r\nbecause of
auto merge.","sha":"f941ba4d6b60cee41c418140e21b677ca0972c71"}}]}]
BACKPORT-->

Co-authored-by: Brad White <Ikuni17@users.noreply.github.com>

.buildkite/scripts/common/util.sh

@@ -36,7 +36,7 @@ check_for_changed_files() {
   GIT_CHANGES="$(git status --porcelain -- . ':!:.bazelrc' ':!:config/node.options')"
 
   if [ "$GIT_CHANGES" ]; then
-    if ! is_auto_commit_disabled && [[ "$SHOULD_AUTO_COMMIT_CHANGES" == "true" && "${BUILDKITE_PULL_REQUEST:-}" != "" && "${BUILDKITE_PULL_REQUEST}" != "false" ]]; then
+    if ! is_auto_commit_disabled && [[ "$SHOULD_AUTO_COMMIT_CHANGES" == "true" && "${BUILDKITE_PULL_REQUEST:-false}" != "false" ]]; then
       NEW_COMMIT_MESSAGE="[CI] Auto-commit changed files from '$1'"
       PREVIOUS_COMMIT_MESSAGE="$(git log -1 --pretty=%B)"