fix: listener silent fail on replica

Update hasql-notifications to include the fix on
https://github.com/diogob/hasql-notifications/issues/24.

Which now reveals the following error:

```
$ postgrest-with-postgresql-16 --replica -f test/spec/fixtures/load.sql postgrest-run

17/May/2024:18:35:38 -0500: Successfully connected to PostgreSQL 16.2 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 13.2.0, 64-bit
17/May/2024:18:35:38 -0500: Could not listen for notifications on the "pgrst" channel. ERROR:  cannot execute LISTEN during recovery
17/May/2024:18:35:38 -0500: Retrying listening for notifications...
```

This is still not good because the LISTEN channel will be retried
forever without a backoff.

src/PostgREST/AppState.hs

@@ -542,23 +542,25 @@ listener appState@AppState{stateObserver=observer, stateMainThreadId=mainThreadI
     dbOrError <- acquire $ toUtf8 (addFallbackAppName prettyVersion configDbUri)
     case dbOrError of
       Right db -> do
-        observer $ DBListenerStart dbChannel
         SQL.listen db $ SQL.toPgIdentifier dbChannel
+        observer $ DBListenStart dbChannel
         SQL.waitForNotifications handleNotification db
 
       Left err -> do
-        observer $ DBListenerFail dbChannel err
+        observer $ DBListenFail dbChannel (Left err)
         exitFailure
   where
     handleFinally dbChannel False err = do
-      observer $ DBListenerFailRecoverObs False dbChannel err
+      observer $ DBListenFail dbChannel (Right err)
       killThread mainThreadId
     handleFinally dbChannel True err = do
       -- if the thread dies, we try to recover
-      observer $ DBListenerFailRecoverObs True dbChannel err
+      observer $ DBListenFail dbChannel (Right err)
       -- assume the pool connection was also lost, call the connection worker
       connectionWorker appState
+
       -- retry the listener
+      observer DBListenRetry
       listener appState conf
 
     handleNotification channel msg =

src/PostgREST/Observation.hs

@@ -40,9 +40,9 @@ data Observation
   | SchemaCacheLoadedObs Double
   | ConnectionRetryObs Int
   | ConnectionPgVersionErrorObs SQL.UsageError
-  | DBListenerStart Text
-  | DBListenerFail Text SQL.ConnectionError
-  | DBListenerFailRecoverObs Bool Text (Either SomeException ())
+  | DBListenStart Text
+  | DBListenFail Text (Either SQL.ConnectionError (Either SomeException ()))
+  | DBListenRetry
   | DBListenerGotSCacheMsg ByteString
   | DBListenerGotConfigMsg ByteString
   | ConfigReadErrorObs SQL.UsageError
@@ -97,12 +97,16 @@ observationMessage = \case
     "Attempting to reconnect to the database in " <> (show delay::Text) <> " seconds..."
   ConnectionPgVersionErrorObs usageErr ->
     jsonMessage usageErr
-  DBListenerStart channel -> do
+  DBListenStart channel -> do
     "Listening for notifications on the " <> show channel <> " channel"
-  DBListenerFail channel err -> do
-    "Could not listen for notifications on the " <> channel <> " channel. " <> show err
-  DBListenerFailRecoverObs recover channel err ->
-    "Could not listen for notifications on the " <> channel <> " channel. " <> showListenerError err <> (if recover then " Retrying listening for notifications.." else mempty)
+  DBListenFail channel listenErr ->
+    "Failed listening for notifications on the " <> show channel <> " channel. " <> (
+      case listenErr of
+        Left err  -> show err
+        Right err -> showListenerError err
+    )
+  DBListenRetry ->
+    "Retrying listening for notifications..."
   DBListenerGotSCacheMsg channel ->
     "Received a schema cache reload message on the " <> show channel <> " channel"
   DBListenerGotConfigMsg channel ->