Add default constructor for exceptions

VpSharp/src/Exceptions/UserNotFoundException.cs

@@ -1,7 +1,15 @@
 namespace VpSharp.Exceptions;
 
+/// <summary>
+///     The exception that is thrown when a user could not be found.
+/// </summary>
 public sealed class UserNotFoundException : Exception
 {
+    /// <inheritdoc />
+    public UserNotFoundException()
+    {
+    }
+
     /// <inheritdoc />
     public UserNotFoundException(string message)
         : base(message)

VpSharp/src/Exceptions/WorldNotFoundException.cs

@@ -5,6 +5,11 @@
 /// </summary>
 public sealed class WorldNotFoundException : Exception
 {
+    /// <inheritdoc />
+    public WorldNotFoundException()
+    {
+    }
+
     /// <inheritdoc />
     public WorldNotFoundException(string worldName)
         : base($"No world with the name {worldName} was found.")