Fix Web IDE tooltip if button is disabled

app/assets/javascripts/vue_merge_request_widget/components/mr_widget_header.vue

@@ -133,19 +133,24 @@ export default {
 
       <div class="branch-actions d-flex">
         <template v-if="mr.isOpen">
-          <gl-button
+          <span
             v-if="!mr.sourceBranchRemoved"
             v-gl-tooltip
-            :href="webIdePath"
             :title="ideButtonTitle"
+            class="gl-display-none d-md-inline-block gl-mr-3"
+            tabindex="0"
+          >
+            <gl-button
+              :href="mr.canPushToSourceBranch ? webIdePath : null"
               :disabled="!mr.canPushToSourceBranch"
-            class="js-web-ide gl-display-none d-md-inline-block gl-mr-3"
+              class="js-web-ide"
               tabindex="0"
               role="button"
               data-qa-selector="open_in_web_ide_button"
             >
               {{ s__('mrWidget|Open in Web IDE') }}
             </gl-button>
+          </span>
           <gl-button
             :disabled="mr.sourceBranchRemoved"
             data-target="#modal_merge_info"