[BUGFIX] Prevent stretching of backend logo

With #94778 the backend logo has been scaled
down to fit into the topbar. This worked but
also led to issues with smaller, such as the
default TYPO3 logo, as those were now stretched.

This is now fixed by removing the "height: auto"
property.

Resolves: #94914
Releases: master
Change-Id: Id3321bf739d0b064b7113ff6a152a088860f44f6
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70672


Tested-by: core-ci <typo3@b13.com>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>

Build/Sources/Sass/scaffold/_topbar.scss

@@ -196,7 +196,6 @@ $toolbar-item-padding-horizontal: 15px;
 
     img {
         max-width: 180px;
-        height: auto;
         max-height: 35px;
         width: auto;
         object-fit: contain;