Correct hardcoded postgrest_test_authenticator (#1743)

Also remove panic from Config and correct io test not running

test/io-tests/configs/expected/no-defaults-with-db-other-authenticator.config

@@ -0,0 +1,27 @@
+db-anon-role = "postgrest_test_anonymous"
+db-channel = "postgrest"
+db-channel-enabled = true
+db-extra-search-path = "public,extensions,other"
+db-max-rows = 100
+db-pool = 1
+db-pool-timeout = 100
+db-pre-request = "test.other_custom_headers"
+db-prepared-statements = false
+db-root-spec = "other_root"
+db-schemas = "test,other_tenant1,other_tenant2"
+db-load-guc-config = "true"
+db-tx-end = "rollback-allow-override"
+db-uri = "<REPLACED_WITH_DB_URI>"
+jwt-aud = "https://otherexample.org"
+jwt-role-claim-key = ".\"other\".\"role\""
+jwt-secret = "ODERREALLYREALLYREALLYREALLYVERYSAFE"
+jwt-secret-is-base64 = true
+log-level = "info"
+openapi-server-proxy-uri = "https://otherexample.org/api"
+raw-media-types = "application/vnd.pgrst.other-db-config"
+server-host = "0.0.0.0"
+server-port = 80
+server-unix-socket = "/tmp/pgrst_io_test.sock"
+server-unix-socket-mode = "777"
+app.settings.test = "test"
+app.settings.test2 = "test"