Keep messages at bottom when textarea is increasing

[NINI1988]

Describe the bug

It would be nice if you enter text into the textarea and the messages would stick to the bottom.
Of course this should happen only if the scroll area was at the bottom before.

Steps to reproduce

1. Go to https://antoine92190.github.io/vue-advanced-chat/
2. Enter multiple lines into textarea with shift+enter
3. The messages will be hidden behind text area

Expected behavior

The message should stick to the bottom

Screenshots

Device (please complete the following information)

• OS: Windows 11
• Browser: Firefox 105, Chrome 106
• Package version: 2.04