[8.x] Auto increase fields limit of the alert indices (elastic#216719) (elastic#218203)

# Backport

This will backport the following commits from `main` to `8.x`:
- [Auto increase fields limit of the alert indices
(elastic#216719)](elastic#216719)

Author: ersin-erdal

x-pack/platform/plugins/shared/alerting/common/alert_schema/field_maps/component_template_from_field_map.ts

@@ -5,7 +5,10 @@
  * 2.0.
  */
 
-import type { ClusterPutComponentTemplateRequest } from '@elastic/elasticsearch/lib/api/types';
+import type {
+  ClusterPutComponentTemplateRequest,
+  MappingDynamicTemplate,
+} from '@elastic/elasticsearch/lib/api/types';
 import { type FieldMap } from '@kbn/alerts-as-data-utils';
 import { mappingFromFieldMap } from './mapping_from_field_map';
 
@@ -14,12 +17,14 @@ export interface GetComponentTemplateFromFieldMapOpts {
   fieldMap: FieldMap;
   includeSettings?: boolean;
   dynamic?: 'strict' | false;
+  dynamicTemplates?: Array<Record<string, MappingDynamicTemplate>>;
 }
 export const getComponentTemplateFromFieldMap = ({
   name,
   fieldMap,
   dynamic,
   includeSettings,
+  dynamicTemplates,
 }: GetComponentTemplateFromFieldMapOpts): ClusterPutComponentTemplateRequest => {
   return {
     name,
@@ -37,7 +42,10 @@ export const getComponentTemplateFromFieldMap = ({
           : {}),
       },
 
-      mappings: mappingFromFieldMap(fieldMap, dynamic ?? 'strict'),
+      mappings: {
+        ...mappingFromFieldMap(fieldMap, dynamic ?? 'strict'),
+        ...(dynamicTemplates ? { dynamic_templates: dynamicTemplates } : {}),
+      },
     },
   };
 };

x-pack/platform/plugins/shared/alerting/server/alerts_service/alerts_service.test.ts

@@ -175,6 +175,7 @@ const getIndexTemplatePutBody = (opts?: GetIndexTemplatePutBodyOpts) => {
               }),
           'index.mapping.ignore_malformed': true,
           'index.mapping.total_fields.limit': 2500,
+          'index.mapping.total_fields.ignore_dynamic_beyond_limit': true,
         },
         mappings: {
           dynamic: false,
@@ -482,6 +483,7 @@ describe('Alerts Service', () => {
                 settings: {
                   ...existingIndexTemplate.index_template.template?.settings,
                   'index.mapping.total_fields.limit': 2500,
+                  'index.mapping.total_fields.ignore_dynamic_beyond_limit': true,
                 },
               },
             },
@@ -916,6 +918,7 @@ describe('Alerts Service', () => {
                         },
                       }),
                   'index.mapping.ignore_malformed': true,
+                  'index.mapping.total_fields.ignore_dynamic_beyond_limit': true,
                   'index.mapping.total_fields.limit': 2500,
                 },
                 mappings: {