[BUG] Bug in create monitor API

[vikhy-aws]

What is the bug?
Currently the create monitor does not throw an error even if action_execution_policy is not specified in the monitor document and creates a monitor. However, the edit monitor UI page breaks if action_execution_policy is not specified in the monitor. So, the monitor creation should be blocked and an appropriate error message should be thrown if action_execution_policy configuration is missing in monitor creation.

How can one reproduce the bug?
Steps to reproduce the behavior:

1. Go to dev tools
2. Create a monitor using the following command after replacing placeholders

POST _plugins/_alerting/monitors
{
  "type": "monitor",
  "schema_version": 8,
  "name": "test monitor",
  "monitor_type": "bucket_level_monitor",
  "enabled": true,
  "enabled_time": 1700000000000,
  "schedule": {
      "period": {
          "interval": 60,
          "unit": "MINUTES"
      }
  },
  "inputs": [
      {
          "search": {
              "indices": [
                  "test-index"
              ],
              "query": {
                  "size": 0,
                  "query": {
                      "bool": {
                          "filter": [
                              {
                                  "term": {
                                      "some_term": {
                                          "value": "some_value",
                                      }
                                  }
                              },
                              {
                                  "match_phrase": {
                                      "message": {
                                          "query": <query>,
                                      }
                                  }
                              },
                              {
                                  "range": {
                                      "@timestamp": {
                                          "from": "{{period_end}}||-1h",
                                          "to": "{{period_end}}",
                                          "include_lower": true,
                                          "include_upper": true,
                                          "boost": 1
                                      }
                                  }
                              }
                          ],
                          "adjust_pure_negative": true,
                          "boost": 1
                      }
                  },
                  "aggregations": {}
              }
          }
      }
  ],
  "triggers": [
      {
          "bucket_level_trigger": {
              "id": "id",
              "name": "trigger name",
              "severity": "2",
              "condition": <some_condition>,
              "actions": [
                  {
                      "id": "id",
                      "name": "notif channel",
                      "destination_id": "id",
                      "message_template": {
                          "source": <source>,
                          "lang": "mustache"
                      },
                      "throttle_enabled": false,
                      "subject_template": {
                          "source": "test",
                          "lang": "mustache"
                      },
                  }
              ]
          }
      }
  ],
  "last_update_time": 1700000000000,
  "data_sources": {
      "query_index": ".opensearch-alerting-queries",
      "findings_index": ".opensearch-alerting-finding-history-write",
      "findings_index_pattern": "<.opensearch-alerting-finding-history-{now/d}-1>",
      "alerts_index": ".opendistro-alerting-alerts",
      "alerts_history_index": ".opendistro-alerting-alert-history-write",
      "alerts_history_index_pattern": "<.opendistro-alerting-alert-history-{now/d}-1>",
      "query_index_mappings_by_type": {},
      "findings_enabled": false
  },
  "owner": "alerting",
  "associated_workflows": [],
  "associatedCompositeMonitorCnt": 0,
  "item_type": "bucket_level_monitor",
  "id": "id",
  "version": 1
}

3. Go to monitor details page and click on edit monitor button to go into edit monitor page.
4. The page breaks.

What is the expected behavior?
Monitor creation should be blocked and an error message should be displayed to the user if action_execution_policy is missing. Also, edit monitor page should not break.

What is your host/environment?

• OS: iOS
• Version: 2.9
• Plugins: Alerting

Do you have any screenshots?
No

Do you have any additional context?
No

[andrross]

Catch All Triage - 1

@AWSHurneyt Can you help find a maintainer to take a look at this?

[AWSHurneyt]

@MohammedAghil has requested to work on this issue. I can't seem to add him as an assignee, so mentioning this in a comment.