[Enhancement] Add rate limiting to yt-dlp requests; prevent saving Media Items when throttled by YouTube (#559)

* Added sleep interval to settings

* Added new sleep setting to yt-dlp runner and added tests

* Added setting for form; updated setting name

* Updated form label

* Prevented saving/updating of media items if being throttled by youtube

* Added the bot message to the list of non-retryable errors

* Fixed typo

test/pinchflat/media_test.exs

@@ -921,6 +921,14 @@ defmodule Pinchflat.MediaTest do
       media_item = media_item_fixture()
       assert %Ecto.Changeset{} = Media.change_media_item(media_item)
     end
+
+    test "validates the title doesn't start with 'youtube video #'" do
+      # This is to account for youtube restricting indexing. See issue #549 for more
+      media_item = media_item_fixture()
+
+      assert %Ecto.Changeset{valid?: false} = Media.change_media_item(media_item, %{title: "youtube video #123"})
+      assert %Ecto.Changeset{valid?: true} = Media.change_media_item(media_item, %{title: "any other title"})
+    end
   end
 
   describe "change_media_item/1 when testing upload_date_index and source is a channel" do