Unskip 'bitwarden installs when enabled' automated test

Closes brave#11357
Follow-up to brave#4776

It should not be skipped since 0.19 as the extension is re-enabled on that version.

Auditors: @bsclifton

Test Plan:
1. Run `npm run test -- --grep='bitwarden installs when enabled'`

test/about/extensionsTest.js

@@ -137,7 +137,7 @@ describe('about:extensions', function () {
         .waitForVisible(`[data-extension-id="${extensionIds[passwordManagers.ENPASS]}"]`, extensionDownloadWaitTime)
     })
   })
-  describe.skip('bitwarden installs when enabled', function () {
+  describe('bitwarden installs when enabled', function () {
     Brave.beforeAll(this)
     before(function * () {
       yield setup(this.app.client)