PITR fails due to wrong `postgres` password

While reproducing #255, after updating `/data/postgresql/postgresql.user.conf` with `max_connections = 320` to try to fix it, I'm now seeing:

```
2024-08-12T20:00:21Z app[3d8dd719a93e78] iad [info]postgres | 2024-08-12 20:00:21.356 UTC [399] FATAL: password authentication failed for user "postgres"
2024-08-12T20:00:21Z app[3d8dd719a93e78] iad [info]postgres | 2024-08-12 20:00:21.356 UTC [399] DETAIL: Connection matched file "/data/postgresql/pg_hba.conf" line 8: "host all all ::0/0 md5"
2024-08-12T20:00:21Z app[3d8dd719a93e78] iad [info]failed post-init: failed to establish connection to local node: failed to connect to `host=fdaa:1:a290:a7b:2f8:8a7c:7dab:2 user=postgres database=postgres`: failed SASL auth (FATAL: password authentication failed for user "postgres" (SQLSTATE 28P01)). Retrying...
2024-08-12T20:00:21Z app[3d8dd719a93e78] iad [info][WARN] `postgres` user password does not match the `OPERATOR_PASSWORD` secret
2024-08-12T20:00:21Z app[3d8dd719a93e78] iad [info][WARN] Use `fly secrets set OPERATOR_PASSWORD= --app db10` to resolve the issue
```