[SLO] add monitor.id to default synthetics groupings (#178455)

## Summary

Ads `monitor.id` to the default synthetics groupings, along with
`monitor.name` and `observer.geo.name`.

This ensures that when a monitor is deleted, and another monitor is
created with the same name, we do not attach the previous monitor's run
to the new monitors SLO calculation.

x-pack/plugins/observability_solution/slo/common/constants.ts

@@ -78,3 +78,4 @@ export const getSLOSummaryPipelineId = (sloId: string, sloRevision: number) =>
   `.slo-observability.summary.pipeline-${sloId}-${sloRevision}`;
 
 export const SYNTHETICS_INDEX_PATTERN = 'synthetics-*';
+export const SYNTHETICS_DEFAULT_GROUPINGS = ['monitor.name', 'observer.geo.name', 'monitor.id'];

x-pack/plugins/observability_solution/slo/public/pages/slo_edit/constants.ts

@@ -30,7 +30,7 @@ import {
   INDICATOR_HISTOGRAM,
   INDICATOR_TIMESLICE_METRIC,
 } from '../../utils/slo/labels';
-import { SYNTHETICS_INDEX_PATTERN } from '../../../common/constants';
+import { SYNTHETICS_DEFAULT_GROUPINGS, SYNTHETICS_INDEX_PATTERN } from '../../../common/constants';
 import { CreateSLOForm } from './types';
 
 export const SLI_OPTIONS: Array<{
@@ -250,7 +250,7 @@ export const SLO_EDIT_FORM_DEFAULT_VALUES_SYNTHETICS_AVAILABILITY: CreateSLOForm
   objective: {
     target: 99,
   },
-  groupBy: ['monitor.name', 'observer.geo.name'],
+  groupBy: SYNTHETICS_DEFAULT_GROUPINGS,
 };
 
 export const COMPARATOR_GT = i18n.translate('xpack.slo.sloEdit.sliType.timesliceMetric.gtLabel', {

x-pack/plugins/observability_solution/slo/server/services/transform_generators/synthetics_availability.test.ts

@@ -77,6 +77,11 @@ describe('Synthetics Availability Transform Generator', () => {
               field: 'observer.geo.name',
             },
           },
+          'slo.groupings.monitor.id': {
+            terms: {
+              field: 'monitor.id',
+            },
+          },
           'slo.id': {
             terms: {
               field: 'slo.id',

x-pack/plugins/observability_solution/slo/server/services/transform_generators/synthetics_availability.ts

@@ -19,6 +19,7 @@ import {
   SLO_DESTINATION_INDEX_NAME,
   SLO_INGEST_PIPELINE_NAME,
   SYNTHETICS_INDEX_PATTERN,
+  SYNTHETICS_DEFAULT_GROUPINGS,
 } from '../../../common/constants';
 import { getSLOTransformTemplate } from '../../assets/transform_templates/slo_transform_template';
 import { InvalidTransformError } from '../../errors';
@@ -53,7 +54,7 @@ export class SyntheticsAvailabilityTransformGenerator extends TransformGenerator
     const groupings =
       flattenedGroupBy.length && !flattenedGroupBy.includes(ALL_VALUE)
         ? slo.groupBy
-        : ['monitor.name', 'observer.geo.name'];
+        : SYNTHETICS_DEFAULT_GROUPINGS;
 
     const hasTags =
       !indicator.params.tags?.find((param) => param.value === ALL_VALUE) &&