Add support for mixing direct member filter with 2FA filter

What does this MR do?

Related to #228675 (closed)

Currently you can not filter group members by "Direct only" and 2FA enabled/disabled, meaning the 2FA filter only works when also displaying inherited group members. This MR adds support for this in preparation for implementing a filtered search bar.

Raw SQL

Before

SELECT
    "members".*
FROM
    "members"
WHERE
    "members"."type" = 'GroupMember'
    AND "members"."source_id" = 9970
    AND "members"."source_type" = 'Namespace'
    AND "members"."requested_at" IS NULL
    AND "members"."access_level" != 5

After

SELECT
    "members".*
FROM
    "members"
    LEFT OUTER JOIN "users" ON "members"."user_id" = "users"."id"
WHERE
    "members"."type" = 'GroupMember'
    AND "members"."source_id" = 9970
    AND "members"."source_type" = 'Namespace'
    AND "members"."requested_at" IS NULL
    AND "members"."access_level" != 5
    AND (EXISTS (
            SELECT
                *
            FROM
                u2f_registrations AS u2f
            WHERE
                u2f.user_id = users.id)
            OR users.otp_required_for_login = TRUE
            OR EXISTS (
                SELECT
                    *
                FROM
                    webauthn_registrations AS webauthn
                WHERE
                    webauthn.user_id = users.id))

Explain Plan

https://explain.depesz.com/s/8GJs

Example of what the filtered search bar will look like

Since the current filter dropdowns will be converted to a filtered search bar in #228675 (closed) this MR does not change the current dropdowns to support this change.

Screenshots (strongly suggested)

Filters	Before	After
2FA: enabled, Direct only
2FA: disabled, Direct only

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] 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