Module Editor: Max character count for Set Lesson Title modal

[jfdoming]

Summary

Add a max character count validation to the "set lesson title" modal.

Goals

• Validate the text field in the modal and prevent users from typing or submitting if they exceed the max character count (100).
• Display counter with # of characters left beneath the text field.

Implementation

Figma: https://www.figma.com/file/Dimm13cjrpYU5LkcrV6VxF/Course-Editor?node-id=703%3A5903

• You can use onKeyDown and just not update the text field text to stop users entering more text once the text field is full.

[draymond63]

This is low priority, probably should be a future ticket