fix: problems discovered during initial 7.0 testing

- Missing translation string for "form" on about page
- Donate button doesn't open in new tab
- Line after choose search engine should only appear on custom
- Line in search setting should not appear when on custom too
- Refresh button on refresh notice does not look great, hover is same as background
- Cards for e.g source and effects need transition
- Version info icon needs hover effect or show on hover
- Back button tooltip only appears on the hovering of the icon

src/scss/_variables.scss

@@ -254,7 +254,7 @@ $themes: (
 
     @if $type == 'modal' {
       background: t($modal-sidebar);
-      border: 3px solid t($modal-sidebarActive);
+      border: 1px solid t($modal-sidebarActive);
       color: t($color);
       border-radius: t($borderRadius);