Update QA E2E specs to reflect vue_project_members_list feature flag

What does this MR do?

Related to #281820 (closed)

I am working on improving the project members view which is now behind the vue_project_members_list feature flag. This MR updates the QA E2E specs to enable the vue_project_members_list feature flag. We are planning on enabling the vue_project_members_list feature flag on gitlab.com later this week and then default to on for the %13.9 release.

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No visual changes, GIF below for context

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
  • Not needed, developer facing change
• [-] Documentation (if required)
  • Being updated in !53096 (merged)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team