remove site-logo support

[gigitux]

Fixes #2145

This PR fixes #2145. Jetpack deprecated the site-logo functionalities, so this PR removes support for it.

At the same time, it will always be possible to customize the logo given that we already support custom-logo (source code)

Screenshots

How to test the changes in this Pull Request:

1. Install Jetpack and activate Storefront
2. Make sure WP_DEBUG is enabled
3. Refresh the page
4. Ensure that you don't see any log like this in debug.log:

PHP Deprecated:  Hook site-logo is deprecated since version 13.4! Use custom-logo instead. Jetpack no longer supports site-logo feature. Add custom-logo support to your theme instead: https://developer.wordpress.org/themes/functionality/custom-logo/ in /srv/htdocs/__wp__/wp-includes/functions.php on line 6078

5. Visit wp-admin/customize.php
6. Go on Site Identity
7. Ensure that you can change the logo

Changelog

Fix – Edit, reply and author icons are now displayed in comment list form. #1319

[nefeline]

Thanks for working on this, @gigitux !

Ensured that there are no errors on debug.log and that it is possible to change the site logo.