Improving github mirror spec flakiness

What does this MR do?

In order to improve pipeline_for_project_mirror_github_spec.rb flakiness #322819 (closed)

Capybara::ElementNotFound:
            Unable to find css "[data-qa-selector=\"project_namespace_select\"],.qa-project-namespace-select" within #<Capybara::Node::Element tag="tr" path="/HTML/BODY[1]/DIV[3]/DIV[1]/DIV[3]/MAIN[1]/DIV[2]/DIV[2]/TABLE[1]/TBODY[1]/TR[13]">

and

Capybara::ElementNotFound:
            Unable to find css "[data-qa-selector=\"personal_access_token_field\"],.qa-personal-access-token-field"

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because _____.
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Related to #322819 (closed)