Remove MessageLimit and MessageExpiration properties

The `AppSettings` class in `AppSettings.cs` has been modified to
remove the `MessageLimit` and `MessageExpiration` properties.
Correspondingly, the `appsettings.json` file has been updated
to remove the `MessageLimit` and `MessageExpiration` settings
under the `AppSettings` section to maintain consistency.

SqlDatabaseVectorSearch/Settings/AppSettings.cs

@@ -10,7 +10,5 @@ public class AppSettings
 
     public int MaxRelevantChunks { get; init; } = 5;
 
-    public int MessageLimit { get; init; }
-
     public TimeSpan MessageExpiration { get; init; }
 }

SqlDatabaseVectorSearch/appsettings.json

@@ -22,7 +22,6 @@
         "MaxTokensPerParagraph": 1024,
         "OverlapTokens": 100,
         "MaxRelevantChunks": 10,
-        "MessageLimit": 20,
         "MessageExpiration": "00:05:00"
     },
     "Logging": {