fix: Remote Note Cleaning will delete notes embedded in a page (#16408)

* feat: preserve number of pages referencing the note

* chore: delete pages on account delete

* fix: notes on the pages are removed by CleanRemoteNotes

* test: add the simplest test for page embedded notes

* fix: section block is not considered

* fix: section block is not considered in migration

* chore: remove comments from columns

* revert unnecessary change

* add pageCount to webhook test

* fix type error on backend

packages/backend/test/unit/NoteCreateService.ts

@@ -40,6 +40,7 @@ describe('NoteCreateService', () => {
 			renoteCount: 0,
 			repliesCount: 0,
 			clippedCount: 0,
+			pageCount: 0,
 			reactions: {},
 			visibility: 'public',
 			uri: null,