PGADMIN_SERVER_JSON_FILE no longer works with current entrypoint.sh

The pgadmin entrypoint.sh no longer supports the --load-servers option but should instead should use load-servers.

See:

• https://github.com/pgadmin-org/pgadmin4/blob/REL-8_8/pkg/docker/entrypoint.sh#L73-L77
• https://github.com/pgadmin-org/pgadmin4/issues/7074#issuecomment-1902795912

The current IronBank entrypoint.sh also overrides the default location of /pgadmin4/servers.json. It is uncertain to me if this is intentional or not.

See:

• https://repo1.dso.mil/dsop/opensource/pgadmin/-/blob/development/scripts/entrypoint.sh?ref_type=heads#L50
• https://github.com/pgadmin-org/pgadmin4/blob/REL-8_8/pkg/docker/entrypoint.sh#L66