fix login scrollbar issue

meets https://community.openproject.org/work_packages/18921

Signed-off-by: Florian Kraft <f.kraft@finn.de>

app/assets/stylesheets/content/_forms.sass

@@ -157,9 +157,9 @@ fieldset
     content: ''
     position: absolute
     margin: 5px 2px
-    /* Length of check tail
+    // Length of check tail
     width: 11px
-    /* Lenght of check foot
+    // Length of check foot
     height: 3px
     background: transparent
     border: 3px solid #666666
@@ -292,6 +292,7 @@ fieldset.form--fieldset
 
 .form--field-extra-actions
   @extend %form--field-after-container
+  overflow-y: visible
 
 %form--field-element-container
   display: block