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/misc/is-renote.ts

@@ -23,6 +23,7 @@ const base: MiNote = {
 	renoteCount: 0,
 	repliesCount: 0,
 	clippedCount: 0,
+	pageCount: 0,
 	reactions: {},
 	visibility: 'public',
 	uri: null,