[Web] Do not show Apps dropdown, when there is only single item

[feldsam]

Contribution Guidelines

• I've read the contribution guidelines and wholeheartedly agree them

What does this PR include?

Short Description

Do not show Apps dropdown in top nav, if there is only single item

Affected Containers

• web

Did you run tests?

What did you tested?

Tested, working good

[FreddleSpl0it]

This does not work as expected. If I only have Webmail as App Link it works, but if I set this in vars.local.inc.php

$MAILCOW_APPS = array(

);

And add only one custom App Link via UI, it still shows a Dropdown.

[feldsam]

Yes, this case is not programed, but for installations with default settings, where is only SOGo, it works.