Include flag_check hook for repo upload in Theme Picker.

See go/sysui-flag-check for details.

Bug: 305147652
Test: Manual
Flag: NA
Change-Id: Ieaa0433fff637637bc4ec5205b4d7baf0f3beea4
diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
index b659bfa..a165f4b 100644
--- a/PREUPLOAD.cfg
+++ b/PREUPLOAD.cfg
@@ -2,3 +2,5 @@
 checkstyle_hook = ${REPO_ROOT}/prebuilts/checkstyle/checkstyle.py --sha ${PREUPLOAD_COMMIT}
 
 ktfmt_hook = ${REPO_ROOT}/external/ktfmt/ktfmt.py --check -i ${REPO_ROOT}/packages/apps/ThemePicker/ktfmt_includes.txt ${PREUPLOAD_FILES}
+
+flag_hook = ${REPO_ROOT}/frameworks/base/packages/SystemUI/flag_check.py --msg=${PREUPLOAD_COMMIT_MESSAGE} --files=${PREUPLOAD_FILES} --project=${REPO_PATH}