[Streams] Add link for downsampling docs in non metrics streams callout

src/platform/packages/shared/kbn-doc-links/src/get_doc_links.ts

@@ -634,6 +634,7 @@ export const getDocLinks = ({ kibanaBranch, buildFlavor }: GetDocLinkOptions): D
       elasticManagedLlm: `${ELASTIC_DOCS}reference/kibana/connectors-kibana/elastic-managed-llm`,
       elasticManagedLlmUsageCost: `${ELASTIC_WEBSITE_URL}pricing`,
       elasticServerlessSearchManagedLlmUsageCost: `${ELASTIC_WEBSITE_URL}pricing/serverless-search`,
+      downsamplingConcepts: `${ELASTIC_DOCS}manage-data/data-store/data-streams/downsampling-concepts`,
     },
     alerting: {
       guide: `${ELASTIC_DOCS}explore-analyze/alerts-cases/alerts/create-manage-rules`,

src/platform/packages/shared/kbn-doc-links/src/types.ts

@@ -453,6 +453,7 @@ export interface DocLinks {
     elasticManagedLlm: string;
     elasticManagedLlmUsageCost: string;
     elasticServerlessSearchManagedLlmUsageCost: string;
+    downsamplingConcepts: string;
   }>;
   readonly alerting: Readonly<{
     authorization: string;

x-pack/platform/plugins/shared/streams_app/public/components/data_management/stream_detail_lifecycle/downsampling/edit_ilm_phases_flyout/edit_ilm_phases_flyout.test.tsx

@@ -7,6 +7,7 @@
 
 import React from 'react';
 import { act, fireEvent, render, screen, waitFor, within } from '@testing-library/react';
+import { I18nProvider } from '@kbn/i18n-react';
 import type { IlmPolicyPhases, PhaseName } from '@kbn/streams-schema';
 import { EditIlmPhasesFlyout } from './edit_ilm_phases_flyout';
 
@@ -94,7 +95,11 @@ const renderFlyout = (
     );
   };
 
-  const { unmount } = render(<Wrapper />);
+  const { unmount } = render(
+    <I18nProvider>
+      <Wrapper />
+    </I18nProvider>
+  );
 
   return {
     onClose,

x-pack/platform/plugins/shared/streams_app/public/components/data_management/stream_detail_lifecycle/downsampling/edit_ilm_phases_flyout/sections/downsample_field_section.tsx

@@ -7,6 +7,7 @@
 
 import React, { useCallback, useEffect } from 'react';
 import { i18n } from '@kbn/i18n';
+import { FormattedMessage } from '@kbn/i18n-react';
 import type { IlmPolicyPhases } from '@kbn/streams-schema';
 import type { FormHook } from '@kbn/es-ui-shared-plugin/static/forms/hook_form_lib';
 import { useFormData } from '@kbn/es-ui-shared-plugin/static/forms/hook_form_lib';
@@ -18,12 +19,14 @@ import {
   EuiTitle,
   EuiCallOut,
   useGeneratedHtmlId,
+  EuiLink,
 } from '@elastic/eui';
 import type { DownsamplePhase, IlmPhasesFlyoutFormInternal } from '../form';
 import { DOWNSAMPLE_PHASES } from '../form';
 import { DownsampleIntervalField } from '../form';
 import { getDoubledDurationFromPrevious, type PreservedTimeUnit } from '../../shared';
 import { TIME_UNIT_OPTIONS } from '../constants';
+import { useKibana } from '../../../../../../hooks/use_kibana';
 
 export interface DownsampleFieldSectionProps {
   form: FormHook<IlmPolicyPhases, IlmPhasesFlyoutFormInternal>;
@@ -67,6 +70,10 @@ export const DownsampleFieldSection = ({
     }
   }, [isEnabled, isReadonlyEnabled, resetReadonly]);
 
+  const {
+    core: { docLinks },
+  } = useKibana();
+
   if (!enabledField) return null;
 
   return (
@@ -179,10 +186,22 @@ export const DownsampleFieldSection = ({
             defaultMessage: 'Downsampling is unavailable for this stream',
           })}
         >
-          {i18n.translate('xpack.streams.editIlmPhasesFlyout.downsamplingNotSupportedBody', {
-            defaultMessage:
-              "Downsampling only works for time series streams. Configuring these settings won't effect how this stream's data is stored.",
-          })}
+          <FormattedMessage
+            id="xpack.streams.editIlmPhasesFlyout.downsamplingNotSupportedBody"
+            defaultMessage="Downsampling only works for time series streams. Configuring these settings won't effect how this stream's data is stored. {learnMoreLink}"
+            values={{
+              learnMoreLink: (
+                <EuiLink
+                  href={docLinks?.links?.observability?.downsamplingConcepts}
+                  target="_blank"
+                >
+                  {i18n.translate('xpack.streams.editIlmPhasesFlyout.downsamplingLearnMoreLink', {
+                    defaultMessage: 'Learn more',
+                  })}
+                </EuiLink>
+              ),
+            }}
+          />
         </EuiCallOut>
       )}