[SuperEditor][AttributedText] Fix placeholder breaking attribution behavior (Resolves #2565)#2566

matthew-carroll merged 2 commits intomainFlutter-Bounty-Hunters/super_editor:mainfrom

2565_empty-text-with-placeholder-crashesFlutter-Bounty-Hunters/super_editor:2565_empty-text-with-placeholder-crashesCopy head branch name to clipboard