pg_control_recovery() return value when not in recovery

Hi,

Just noticed that we're returning the underlying values for
pg_control_recovery() without any checks:
postgres[14388][1]=# SELECT * FROM pg_control_recovery();
┌──────────────────────┬───────────────────────────┬──────────────────┬────────────────┬───────────────────────────────┐
│ min_recovery_end_lsn │ min_recovery_end_timeline │ backup_start_lsn │ backup_end_lsn │ end_of_backup_record_required │
├──────────────────────┼───────────────────────────┼──────────────────┼────────────────┼───────────────────────────────┤
│ 0/0 │ 0 │ 0/0 │ 0/0 │ f │
└──────────────────────┴───────────────────────────┴──────────────────┴────────────────┴───────────────────────────────┘
(1 row)

postgres[14388][1]=# SELECT pg_is_in_recovery();
┌───────────────────┐
│ pg_is_in_recovery │
├───────────────────┤
│ f │
└───────────────────┘
(1 row)

Wouldn't it be more accurate to return NULLs here?

Greetings,

Andres Freund