Fix label width oversize bug

Happens at Firefox zoom level 90%, probably on Windows...

Fixes: https://github.com/wekan/wekan/pull/4073#issuecomment-971563178

client/components/cards/labels.styl

@@ -146,6 +146,7 @@
     height: 25px
     margin: 0px 3% 7px 0px
     width: 10.5%
+    max-width: 10.5%
     cursor: pointer
 
 .edit-labels