Settings: Update site icon preview while typing site title

[swissspidy]

When changing the site title under Settings -> General, we automatically update the title in the toolbar while typing.

Example: ​https://imgur.com/a/sl5QKoM

The same can be done for the site icon preview as well.

[jorbin]

This is resolved in ​https://github.com/WordPress/wordpress-develop/pull/6109 with ​https://github.com/WordPress/wordpress-develop/pull/6109/commits/254a28866869ebbf05a8cafc37cd4f18837f29b1

I think this can be closed as dupe of #54370

[swissspidy]

Duplicate of #54370.

Oh neat, I didn't this was implemented there. I should have tried it there. I'll leave my feedback there. Thanks!