[SIEM] Remove placeholder from pinned event tooltips (#52361)

## [SIEM] Remove placeholder from pinned event tooltips

Similar to signals, pinned timeline events should be copied from source indexes, which are subject to ILM, to separate (space-aware) indexes (with different ILM), such that pinned events can be viewed in a timeline after the events have aged out of the original indexes.

The backend APIs and UI patterns in development now for signals can likely be reused to implement the above, but until then, the placeholder tooltip text for unpinned / pinned events, which mentions persistence, should be removed from the SIEM beta.

- [x] Changed the _unpinned_ event tooltip text from (sic) `This is event is NOT persisted with the timeline` to `Unpinned event`
- [x] Changed the pinned event tooltip text from `This event is persisted with the timeline` to `Pinned event`

elastic/siem-team#482

x-pack/legacy/plugins/siem/public/components/timeline/body/helpers.test.ts

@@ -203,28 +203,22 @@ describe('helpers', () => {
   });
 
   describe('getPinTooltip', () => {
-    test('it informs the user the event may not be unpinned when the event is pinned and has notes', () => {
+    test('it indicates the event may NOT be unpinned when `isPinned` is `true` and the event has notes', () => {
       expect(getPinTooltip({ isPinned: true, eventHasNotes: true })).toEqual(
         'This event cannot be unpinned because it has notes'
       );
     });
 
-    test('it tells the user the event is persisted when the event is pinned, but has no notes', () => {
-      expect(getPinTooltip({ isPinned: true, eventHasNotes: false })).toEqual(
-        'This event is persisted with the timeline'
-      );
+    test('it indicates the event is pinned when `isPinned` is `true` and the event does NOT have notes', () => {
+      expect(getPinTooltip({ isPinned: true, eventHasNotes: false })).toEqual('Pinned event');
     });
 
-    test('it tells the user the event is NOT persisted when the event is not pinned, but it has notes', () => {
-      expect(getPinTooltip({ isPinned: false, eventHasNotes: true })).toEqual(
-        'This is event is NOT persisted with the timeline'
-      );
+    test('it indicates the event is NOT pinned when `isPinned` is `false` and the event has notes', () => {
+      expect(getPinTooltip({ isPinned: false, eventHasNotes: true })).toEqual('Unpinned event');
     });
 
-    test('it tells the user the event is NOT persisted when the event is not pinned, and has no notes', () => {
-      expect(getPinTooltip({ isPinned: false, eventHasNotes: false })).toEqual(
-        'This is event is NOT persisted with the timeline'
-      );
+    test('it indicates the event is NOT pinned when `isPinned` is `false` and the event does NOT have notes', () => {
+      expect(getPinTooltip({ isPinned: false, eventHasNotes: false })).toEqual('Unpinned event');
     });
   });
 

x-pack/legacy/plugins/siem/public/components/timeline/body/translations.ts

@@ -21,11 +21,11 @@ export const COPY_TO_CLIPBOARD = i18n.translate(
 );
 
 export const UNPINNED = i18n.translate('xpack.siem.timeline.body.pinning.unpinnedTooltip', {
-  defaultMessage: 'This is event is NOT persisted with the timeline',
+  defaultMessage: 'Unpinned event',
 });
 
 export const PINNED = i18n.translate('xpack.siem.timeline.body.pinning.pinnedTooltip', {
-  defaultMessage: 'This event is persisted with the timeline',
+  defaultMessage: 'Pinned event',
 });
 
 export const PINNED_WITH_NOTES = i18n.translate(