Merge branch 'keep-committing-spinner-when-conflict-resolved' into 'master'

Keep committing ... spinner when conflict resolved

## What does this MR do?

When a conflict is resolved successfully, keep the 'committing ...' spinner until the new page loads rather than showing the standard button again, which is misleading. The old behaviour looks like this:

![Resolve_merge_conflict](/uploads/8e0efec0bb4b1358d4dd3353ea1dc57b/Resolve_merge_conflict.gif)

I don't think this needs a CHANGELOG entry as it's pretty minor.

See merge request !5892

app/assets/javascripts/merge_conflict_resolver.js.es6

@@ -75,10 +75,8 @@ class MergeConflictResolver {
         window.location.href = data.redirect_to;
       })
       .error(() => {
-        new Flash('Something went wrong!');
-      })
-      .always(() => {
         this.vue.isSubmitting = false;
+        new Flash('Something went wrong!');
       });
   }