chore(frontend-files): add a light border to Collabora editor

Author: johaven

frontend/src/app/applications/files/components/viewers/files-viewer-collabora-online.component.ts

@@ -14,7 +14,7 @@ import { fileLockPropsToString } from '../utils/file-lock.utils'
   selector: 'app-files-viewer-collabora-online',
   template: `
     @if (documentServerUrl) {
-      <div [style.height.px]="currentHeight()">
+      <div class="app-collabora-online-border" [style.height.px]="currentHeight()">
         <iframe
           [src]="documentServerUrl"
           class="app-viewer-iframe collabora-scaling"

frontend/src/styles/components/_app.scss

@@ -515,3 +515,7 @@ app-input-filter {
     padding: .15rem .3rem;
   }
 }
+
+.app-collabora-online-border {
+  border-top: .5px solid mix($sidebar-light-icons-menu-hover-bg, $primary, 50%);
+}