Remove invite team members sidebar link

What does this MR do?

• removes the link from the sidebar for inviting members in the group/project scope.

How to test locally

• enable invite_members_group_modal globally via bundle exec rails console, then entering...

Feature.enable(:invite_members_group_modal)

• visit a group or project you are a maintainer or owner on to validate there is no link.

Screenshots (strongly suggested)

Should be the reverse of images here - link before/no link after

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 the link is behind a feature flag.
• Documentation (if required)
• 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

Related to #323134