Feature: maxLength for read-only mode

We are using Lexical for our app in both editable and read-only mode. So far, really good! We use the in-built read-only mode to display content the user has submitted. A new requirement arose that content in the read-only mode needed to be trimmed to n places. I tried modifying the maxLength plugin from #2230 but with read-only and a default editor value, I couldn't make it work.

Ideally we would like to use this feature to show a snippet of a longer user submitted introduction text and show the entirety of the text in a separate dialog.

Start by reviewing the maxLength plugin referenced in #2230 and how Lexical handles read-only mode with a default editor value. Confirm how a length limit should apply in read-only mode, then verify that longer submitted text is trimmed while content at or below the limit remains unchanged.

Written by the indexing model from the issue text.