Correct the `blocked` scope in `Member` class

What does this MR do?

The issue has been described in detail @ !54587 (comment 568522191)

Ideally, the blocked scope should be excluding the invited users. However, the existing scope's code does not exclude them.

However, due to the (incorrect) way in which we were creating invited users in specs, the specs for blocked scope never failed even though the method implementation was incorrect.

Now that we are creating invited members in specs the right way, the specs failed and hence the implementation of blocked scope has now been corrected 🙂

Screenshots (strongly suggested)

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

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