Use data attribute for storage counter spec

ee/app/assets/javascripts/storage_counter/components/app.vue

@@ -60,7 +60,7 @@ export default {
       <div class="row py-0">
         <div class="col-sm-12">
           <strong>{{ s__('UsageQuota|Storage usage:') }}</strong>
-          <span class="js-total-usage">
+          <span data-testid="total-usage">
             {{ namespace.totalUsage }}
             <gl-link
               :href="helpPagePath"

ee/spec/frontend/storage_counter/components/app_spec.js

@@ -52,7 +52,7 @@ describe('Storage counter app', () => {
       wrapper.vm
         .$nextTick()
         .then(() => {
-          expect(wrapper.find('.js-total-usage').text()).toContain(
+          expect(wrapper.find("[data-testid='total-usage']").text()).toContain(
             withRootStorageStatistics.totalUsage,
           );
         })
@@ -70,7 +70,7 @@ describe('Storage counter app', () => {
       wrapper.vm
         .$nextTick()
         .then(() => {
-          expect(wrapper.find('.js-total-usage').text()).toContain('N/A');
+          expect(wrapper.find("[data-testid='total-usage']").text()).toContain('N/A');
         })
         .then(done)
         .catch(done.fail);