Deprecation: #92628 - Login Logo without Alt-Text 

See forge#92628

Description 

The configuration of the extension "backend" has now the possibility to provide an alt-text for a custom login logo.

As an alt-text is needed for accessibility reasons, not setting an alt-text has been marked as deprecated.

Impact 

Not configuring an alt-text will trigger a PHP E_USER_DEPRECATED error.

Affected Installations 

All instances that have defined a custom login logo are affected.

Migration 

Configure an alt-text for your custom login logo.