[ResponseOps] Snooze Scheduler UX for recurring snoozes shows incorrect summary (#214797)

Solves: https://github.com/elastic/kibana/issues/210119

## Summary

How to test:
Reproduce bug from an issue. But create a rule in Stack management.
Action is not needed. You can test it on main.
![Screenshot 2025-03-19 at 20 43
09](https://github.com/user-attachments/assets/2b311a28-c474-4883-8f75-34f9de87a493)

![Screenshot 2025-03-19 at 20 46
56](https://github.com/user-attachments/assets/894e26c6-b298-40c2-9d6a-c5fd460300d2)

When you add new schedule and save it, you should see proper date here
as well:

![Screenshot 2025-03-19 at 20 59
53](https://github.com/user-attachments/assets/28239de4-ee99-4e51-a88a-ca78e5248f5f)


### Checklist

Check the PR satisfies following conditions. 

Reviewers should verify this PR satisfies this list as well.

- [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/platform/plugins/shared/triggers_actions_ui/public/application/sections/rules_list/components/rule_snooze/panel/helpers.test.tsx

@@ -71,5 +71,22 @@ describe('Snooze panel helpers', () => {
         })
       ).toEqual('Every month on the 4th Tuesday for 5 occurrences');
     });
+
+    test('should capitalize first letter and display correct month for yearly recurrence', () => {
+      expect(
+        scheduleSummary({
+          id: null,
+          duration: 864000,
+          rRule: {
+            dtstart: NOW,
+            tzid: 'UTC',
+            freq: RRuleFrequency.YEARLY,
+            interval: 1,
+            bymonth: [3],
+            bymonthday: [21],
+          },
+        })
+      ).toEqual('Every year on March 21');
+    });
   });
 });

x-pack/platform/plugins/shared/triggers_actions_ui/public/application/sections/rules_list/components/rule_snooze/recurrence_scheduler/helpers.test.tsx

@@ -133,6 +133,17 @@ describe('Recurrence scheduler helper', () => {
       ).toEqual('every month on the 4th Tuesday');
     });
 
+    test('should display correct month name for yearly recurrence', () => {
+      expect(
+        recurrenceSummary({
+          freq: RRuleFrequency.YEARLY,
+          interval: 1,
+          bymonth: [3],
+          bymonthday: [18],
+        })
+      ).toEqual('every year on March 18');
+    });
+
     test('should give a basic msg', () => {
       expect(
         recurrenceSummary({
@@ -280,7 +291,7 @@ describe('Recurrence scheduler helper', () => {
           startDate: moment('11/23/2021'),
         })
       ).toEqual({
-        bymonth: [10],
+        bymonth: [11],
         bymonthday: [23],
         byweekday: [],
         freq: 0,

x-pack/platform/plugins/shared/triggers_actions_ui/public/application/sections/rules_list/components/rule_snooze/recurrence_scheduler/helpers.tsx

@@ -109,7 +109,11 @@ export const recurrenceSummary = ({
       ? i18n.translate('xpack.triggersActionsUI.ruleSnoozeScheduler.bymonthSummary', {
           defaultMessage: 'on {date}',
           values: {
-            date: i18nMonthDayDate(moment().month(bymonth[0]).date(bymonthday[0])),
+            date: i18nMonthDayDate(
+              moment()
+                .month(bymonth[0] - 1)
+                .date(bymonthday[0])
+            ),
           },
         })
       : null;
@@ -179,7 +183,7 @@ export const buildCustomRecurrenceSchedulerState = ({
       : [];
 
   const bymonthday = useByMonthDay ? [startDate.date()] : [];
-  const bymonth = startDate && frequency === RRuleFrequency.YEARLY ? [startDate.month()] : [];
+  const bymonth = startDate && frequency === RRuleFrequency.YEARLY ? [startDate.month() + 1] : [];
   return {
     freq: frequency,
     interval,