UI enhancement fixes (#3222)

- Added min-width and min-height to Display Layout lines to allow
 easier selection and move when line is purely vertical or horizontal;
 - Fixed spacing, size and icon of overlay close button;

src/plugins/displayLayout/components/LineView.vue

@@ -76,8 +76,8 @@ const START_HANDLE_QUADRANTS = {
     2: 'c-frame-edit__handle--se',
     3: 'c-frame-edit__handle--ne',
     4: 'c-frame-edit__handle--nw',
-    5: 'c-frame-edit__handle--ne',
-    6: 'c-frame-edit__handle--se'
+    5: 'c-frame-edit__handle--nw',
+    6: 'c-frame-edit__handle--ne'
 };
 
 const END_HANDLE_QUADRANTS = {

src/plugins/displayLayout/components/box-and-line-views.scss

@@ -46,6 +46,11 @@
     }
 
     .is-editing & {
+        // Needed to allow line to be moved
+        $w: 4px;
+        min-width: $w;
+        min-height: $w;
+
         &:hover {
             [class*='__hover-indicator'] {
                 display: inline;