Enable `vue_2fa_recovery_codes` feature flag by default

What does this MR do?

Related to #290113 (closed) and #267730 (closed)

Change introduced in !49078 (merged)

Enables the vue_2fa_recovery_codes feature flag by default. Has been enabled on gitlab.com since 12/14.

To encourage users to save their 2FA recovery codes the vue_2fa_recovery_codes FF enables a new view that adds "Copy codes", "Download codes" and "Print codes" buttons to the recovery codes view. It also disables the "Proceed" button until the the user has either copied, downloaded, or printed their codes.

Screenshots (strongly suggested)

Page	Before	After
Recovery codes
Recovery codes - Proceed enabled	N/A
Account after clicking "Proceed"

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