fix(CardBrowser): mark all if mixed selection

If there is a mix of marked and unmarked notes selected,
'toggle mark' should mark all the notes

If all notes are marked, remove the mark
If no notes are marked, add the mark

This restores previous behaviour

Changed in 7a65160
non-squashed: [4846711]

Fixes 14821

AnkiDroid/src/main/java/com/ichi2/anki/CardBrowser.kt

@@ -674,8 +674,11 @@ open class CardBrowser :
         val cardIds = selectedCardIds
         withProgress {
             undoableOp {
-                val wantMark = !getCard(selectedCardIds.first()).note().hasTag("marked")
                 val noteIds = notesOfCards(cardIds)
+                // if all notes are marked, remove the mark
+                // if no notes are marked, add the mark
+                // if there is a mix, enable the mark on all
+                val wantMark = !noteIds.all { getNote(it).hasTag("marked") }
                 if (wantMark) {
                     tags.bulkAdd(noteIds, "marked")
                 } else {