roachtest: backup-restore/mixed-version failed about cockroach

[msbutler]

Well this is an odd one. We got the following error after restore completed. I guess restore forgot to turn the schema back online?

Wraps: (4) error computing contents for backup 2_v22.2.19-to-v23.1.21_full-planned-and-executed-on-v23.1.21-incremental-planned-and-executed-on-v22.2.19_cluster
Wraps: (5) error running command (./cockroach sql --certs-dir certs -e "SELECT * FROM [SHOW GRANTS] AS OF SYSTEM TIME '1718178368013552384.0000000000'" --port {pgport:1})
Wraps: (6) Node 1. Command with error:
  | ```
  | ./cockroach sql --certs-dir certs -e "SELECT * FROM [SHOW GRANTS] AS OF SYSTEM TIME '1718178368013552384.0000000000'" --port {pgport:1}
  | ```
  | stdout: <empty>
  | stderr:ERROR: schema "public" is offline: restoring
  | Failed running "sql"

[msbutler]

ah, thanks to the excellent logging, we were in the following mixed version state, which implies that the previous restore was non-mvcc:

(1) test failed:
  | test random seed: 6463111699098982353
  |
  |                                     n1           n2           n3           n4
  | released versions                   v22.2.19     v22.2.19     v22.2.19     v23.1.21
  | logical binary versions             22.2         22.2         22.2         23.1
  | cluster versions before failure     22.2         22.2         22.2         22.2
  | cluster versions after failure      22.2         22.2         22.2         22.2

Given that 22.2 is out of support, i'm not going to investigate this further.