LDAP support for OID 1.3.6.1.4.1.4203.1.11.3 (whoami)

### Is your feature request related to a problem?

Authentik's LDAP Provider/Outpost doesn't have support for OID 1.3.6.1.4.1.4203.1.11.1 and 1.3.6.1.4.1.4203.1.11.3. The former is for secure password changes (which probably aren't necessary) and the latter is akin to a `whoami` command.

### Describe the solution you'd like

I'm not sure how necessary this is, but at least having support for 1.3.6.1.4.1.4203.1.11.3 (Whoami) would be nice. Other IDPs use it when looking for a user, so if Authentik had support for this, it could be easier to link it with other IDPs or services

### Describe alternatives that you've considered

Searching ldap with cn set to yourself works, but whoami is the "official" way

### Additional context

_No response_

Start by tracing how the LDAP Provider/Outpost handles extended LDAP operations, then identify the existing tests for LDAP requests. Verify the 1.3.6.1.4.1.4203.1.11.3 request against the expected authenticated identity; done means LDAP clients can use Whoami successfully.

Written by the indexing model from the issue text.