Refactor RestType null check with pattern matching

Refactored the null check for action.RestType to use pattern matching, assigning it to a local variable restType if not null. Now throws DataIntegrityException if RestType is null, and uses restType for creating the HttpRequestMessage. This improves code clarity and ensures RestType is non-null in subsequent logic.

src/ReC.Application/RecActionViews/Commands/InvokeRecActionViewCommand.cs

@@ -35,14 +35,14 @@ public class InvokeRecActionViewCommandHandler(
 
         using var http = clientFactory.CreateClient(Http.ClientName);
 
-        if (action.RestType is null)
+        if (action.RestType is not RestType restType)
             throw new DataIntegrityException(
                 $"Rec action could not be invoked because the RestType value is null. " +
                 $"ProfileId: {action.ProfileId}, " +
                 $"Id: {action.Id}"
             );
 
-        using var httpReq = action.RestType
+        using var httpReq = restType
             .ToHttpMethod()
             .ToHttpRequestMessage(action.EndpointUri);