bk: fix regex and add new file (elastic#18382)

Author: v1v

.buildkite/pull-requests.json

@@ -46,9 +46,8 @@
 			"set_commit_status": true,
 			"build_on_commit": true,
 			"build_on_comment": true,
-			"trigger_comment_regex": "^/?run\s+exhaustive\s+tests$",
-			"always_trigger_comment_regex": "^/?run\s+exhaustive\s+tests$",
-			"always_trigger_comment_regex": "^(?:(?:/run\\W+)(?:exhaustive)\\W+(?:tests))",
+			"trigger_comment_regex": "^/?run\\s+exhaustive\\s+tests$",
+			"always_trigger_comment_regex": "^/?run\\s+exhaustive\\s+tests$",
 			"skip_ci_labels": [],
 			"skip_target_branches": [],
 			"skip_ci_on_only_changed": [
@@ -59,7 +58,8 @@
 				"\\.md$"
 			],
 			"always_require_ci_on_changed": [
-				"^qa/acceptance/"
+				"^qa/acceptance/",
+				"^ci/acceptance_tests.sh"
 			]
 		}
 	]