[telemetry][ColorPicker] add event name support (#10476)

Allow to set a custom name for the event instead of just using the
class name.

src/common/ManagedTelemetry/Telemetry/Events/EventBase.cs

@@ -16,6 +16,8 @@ namespace Microsoft.PowerToys.Telemetry.Events
     {
         public bool UTCReplace_AppSessionGuid => true;
 
+        public string EventName { get; set; }
+
         private string _version;
 
         public string Version