Prevent conflict with pdf and external link styles

* By using :before instead of :after.
* Remove the pseudo element text in the editor.
* Only show the outline of the first link while the parent block has
focus within.

assets/src/styles/editorStyle.scss

@@ -28,22 +28,12 @@
 @import "editorFonts";
 
 .is-style-expand-link {
-  a {
+  &:focus-within a {
     outline: 1px dashed grey;
     outline-offset: 2px;
   }
 
   a:not(:first-of-type) {
     outline: 2px solid red;
   }
-
-  &:before {
-    content: "Entirely clickable";
-    position: absolute;
-    bottom: -24px;
-    left: 8px;
-    font-size: 14px;
-    font-style: italic;
-    color: grey;
-  }
 }

assets/src/styles/style.scss

@@ -10,12 +10,18 @@
 .is-style-expand-link {
   position: relative;
 
-  a:after {
-    content: "";
-    position: absolute;
-    top: 0;
-    left: 0;
-    bottom: 0;
-    right: 0;
+  a {
+    &:before {
+      content: "";
+      position: absolute;
+      top: 0;
+      left: 0;
+      bottom: 0;
+      right: 0;
+    }
+
+    &:after {
+      display: none;
+    }
   }
 }