Fix alignment of MR conflict resolution

app/assets/stylesheets/bootstrap_migration.scss

@@ -46,12 +46,6 @@ a {
   text-align: right;
 }
 
-.form-control,
-.search form {
-  // Bootstrap 4 does not have a height
-  height: 34px;
-}
-
 table {
   // Remove any table border lines
   border-spacing: 0;

app/views/projects/merge_requests/conflicts/_submit_form.html.haml

@@ -15,7 +15,7 @@
         .max-width-marker
         %textarea.form-control.js-commit-message#commit-message{ "v-model" => "conflictsData.commitMessage", "rows" => "5" }
   .form-group.row
-    .col-md-offset-4.col-md-8
+    .offset-md-4.col-md-8
       .row
         .col-6
           %button.btn.btn-success.js-submit-button{ type: "button", "@click" => "commit()", ":disabled" => "!readyToCommit" }