Ensure design image has max-height 100%

This change reverts the added behviour where an image
would default to 100% width and be allowed to
overflow vertically.

Reverted because of the additional UX complexities
identified during review.

ee/app/assets/javascripts/design_management/components/image.vue

@@ -52,7 +52,7 @@ export default {
 </script>
 
 <template>
-  <div class="m-auto js-design-image">
+  <div class="m-auto h-100 w-100 d-flex-center js-design-image">
     <img ref="contentImg" :src="image" :alt="name" class="img-fluid mh-100" @load="onImgLoad" />
   </div>
 </template>

ee/spec/frontend/design_management/components/__snapshots__/image_spec.js.snap

@@ -2,7 +2,7 @@
 
 exports[`Design management large image component renders image 1`] = `
 <div
-  class="m-auto js-design-image"
+  class="m-auto h-100 w-100 d-flex-center js-design-image"
 >
   <img
     alt="test"
@@ -14,7 +14,7 @@ exports[`Design management large image component renders image 1`] = `
 
 exports[`Design management large image component renders loading state 1`] = `
 <div
-  class="m-auto js-design-image"
+  class="m-auto h-100 w-100 d-flex-center js-design-image"
   isloading="true"
 >
   <img