Fixed hover outline on inline image selector

refs https://github.com/TryGhost/Team/issues/1225

- static outline was removed but we were still showing an outline when hovered
- added `media-card-placeholder` kg-style case that is the same as `media-card` but without the `kg-card-hover` class

ghost/admin/lib/koenig-editor/addon/components/koenig-card-image.hbs

@@ -1,6 +1,6 @@
 <KoenigCard
     @tagName="figure"
-    @class={{concat (kg-style "media-card") " " (kg-style "breakout" size=this.payload.cardWidth) " flex flex-column"}}
+    @class={{concat (kg-style (if (eq this.imageSelector.type "placeholder") "media-card-placeholder" "media-card")) " " (kg-style "breakout" size=this.payload.cardWidth) " flex flex-column"}}
     @showSelectedOutline={{not-eq this.imageSelector.type "placeholder"}}
     @isSelected={{this.isSelected}}
     @isEditing={{this.isEditing}}

ghost/admin/lib/koenig-editor/addon/helpers/kg-style.js

@@ -41,6 +41,9 @@ export function kgStyle([style], options) {
     case 'media-card':
         cssClass = `${pFontStyle} ma0 ba b--transparent kg-card-hover`;
         break;
+    case 'media-card-placeholder':
+        cssClass = `${pFontStyle} ma0 ba b--transparent`;
+        break;
 
     // Media styles & figure caption
     case 'image-normal':