Expand web TextInput as the user types

[Jag96]

Fixes #103

Tests

1. Type in the textbox on web, android, and iOS, confirm the textbox grows as you type
2. Delete text in the textbox using backspace, confirm the textbox resizes as you delete
3. Paste a chunk of text or delete a chunk of text, confirm the textbox resizes properly

[Jag96]

Going to be OOO until 8/31, if this needs to be updated feel free to ping somebody else to update. If not, I'll get back to it then!

[marcaaron]

Just wondering should we put a limit on the height of the text box?

[marcaaron]

LGTM and works well!

[marcaaron]

Gonna hold off merging this until next week in case it breaks something (doesn't look like it should)

[shawnborton]

What's the latest on this one?

[shawnborton]

I agree that a max-height for the input would be great.

[JmillsExpensify]

Heads up, I just moved the related issue to high. We're already running into this on a daily basis, and is a very important component of moving DMs into RNC.

[marcaaron]

This fell off my radar while helping out implement DMs. Merging now so we should be 👍