Prevent <ProfileHeaderHandle /> from breaking out of its parent view

[HorusGoul]

What changes?
Sets a max width of 100% for the ProfileHeaderHandle component to prevent it from overflowing in views like Settings.

Fixes #6569.

How to test
The easiest way is to clone the branch, replace this line with a very long handle and visualize the changes:
https://github.com/HorusGoul/bsky-social-app/blob/a7aaeaec11dba45d1c1654b2cd6c5ed344d669bc/src/screens/Profile/Header/Handle.tsx#L52

I used this handle: @verylonghandlewithsomanycharacters.thatitmightbreaktheblueskyimplementationforhandles.orletsseehowthisshowsupintheuilol.hibtwandimsosorry.therearestillsomanymorecharacterstofillidk.imightaswellgototwohundredorsomethinglikethat.bye.horus.dev

Screenshot showing the fix
The issue seems to be present on Web but not on Android. I can't check iOS at the moment.

Before (production)	After (this branch, localhost)

Testing for both short and long handles:

Settings:

Profile:

Labeler profile:

[mozzius]

lovely, thank you!