Fix app nav img margin

[skjnldsv]

Fix #6622
@nextcloud/designers

[juliusknorr]

@skjnldsv Also happens to be an issue without an image, see the app management:

[skjnldsv]

@juliushaertl This is @jancborchardt's will. He wants users to be 'forced' to have some icons! :)
#6399 (comment)

[juliusknorr]

Ah ok, is there already an issue for the parts missing an icon in the server repo?

[skjnldsv]

You mean in the apps management section?

[codecov]

Codecov Report

Merging #6623 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #6623      +/-   ##
============================================
- Coverage     53.06%   53.06%   -0.01%     
  Complexity    22553    22553              
============================================
  Files          1414     1414              
  Lines         87745    87745              
  Branches       1340     1340              
============================================
- Hits          46565    46564       -1     
- Misses        41180    41181       +1

Impacted Files	Coverage Δ	Complexity Δ
apps/files_trashbin/lib/Trashbin.php	72.28% <0%> (-0.25%)	136% <0%> (ø)

[skjnldsv]

@nextcloud/designers please review :)

[juliusknorr]

@skjnldsv Yes. Found it #3987

[jancborchardt]

@skjnldsv see, it pushes us to add icons ;)

[skjnldsv]

@jancborchardt well done fine sir! You tricked me well! 😱😱