Follow up (#116860)

## Summary

One line follow up from #116490 from @dhurley14 here: #116490 (comment)


### Checklist

- [x] [Unit or functional tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html) were updated or added to match the most common scenarios

x-pack/plugins/security_solution/server/lib/detection_engine/routes/rules/utils.test.ts

@@ -534,6 +534,7 @@ describe.each([
 
   describe('getTupleDuplicateErrorsAndUniqueRules', () => {
     test('returns tuple of empty duplicate errors array and rule array with instance of Syntax Error when imported rule contains parse error', async () => {
+      // This is a string because we have a double "::" below to make an error happen on purpose.
       const multipartPayload =
         '{"name"::"Simple Rule Query","description":"Simple Rule Query","risk_score":1,"rule_id":"rule-1","severity":"high","type":"query","query":"user.name: root or user.name: admin"}\n';
       const ndJsonStream = new Readable({
@@ -657,6 +658,7 @@ describe.each([
     });
 
     test('returns empty errors array and rule array with instance of Syntax Error when imported rule contains parse error', async () => {
+      // This is a string because we have a double "::" below to make an error happen on purpose.
       const multipartPayload =
         '{"name"::"Simple Rule Query","description":"Simple Rule Query","risk_score":1,"rule_id":"rule-1","severity":"high","type":"query","query":"user.name: root or user.name: admin"}\n';
       const ndJsonStream = new Readable({

x-pack/plugins/security_solution/server/lib/detection_engine/routes/rules/utils.ts

@@ -208,15 +208,15 @@ export const getInvalidConnectors = async (
   actionsClient: ActionsClient
 ): Promise<[BulkError[], PromiseFromStreams[]]> => {
   const actionsFind = await actionsClient.getAll();
-  const actionIds = actionsFind.map((action) => action.id);
+  const actionIds = new Set(actionsFind.map((action) => action.id));
   const { errors, rulesAcc } = rules.reduce(
     (acc, parsedRule) => {
       if (parsedRule instanceof Error) {
         acc.rulesAcc.set(uuid.v4(), parsedRule);
       } else {
         const { rule_id: ruleId, actions } = parsedRule;
         const missingActionIds = actions.flatMap((action) => {
-          if (actionIds.find((actionsId) => actionsId === action.id) == null) {
+          if (!actionIds.has(action.id)) {
             return [action.id];
           } else {
             return [];