fix null dereferences in ensure expected content type method

Author: Fresa

src/OpenAPI.WebApiGenerator/CodeGeneration/ResponseGenerator.cs

@@ -14,6 +14,7 @@ public SourceCode GenerateResponseClass(string @namespace, string path)
 $$"""
 #nullable enable
 using Corvus.Json;
+using System.Net.Http.Headers;
 using System.Text.Json;
 using {{httpResponseExtensionsGenerator.Namespace}};
 
@@ -47,8 +48,9 @@ protected void EnsureExpectedContentType(MediaTypeHeaderValue contentType, Media
         {
             "*/*" => true,
             not null when expectedContentType.MediaType.EndsWith("*") =>
-                contentType.MediaType?.StartsWith(expectedContentType.MediaType.TrimEnd('*'), StringComparison.OrdinalIgnoreCase),
-            _ => contentType.MediaType.Equals(expectedContentType.MediaType, StringComparison.OrdinalIgnoreCase)
+                contentType.MediaType?.StartsWith(expectedContentType.MediaType.TrimEnd('*'), StringComparison.OrdinalIgnoreCase) ?? false,
+            not null => contentType.MediaType?.Equals(expectedContentType.MediaType, StringComparison.OrdinalIgnoreCase) ?? false,
+            _ => false
         };
         
         if (valid)

tests/Example.OpenApi32/Paths/FooFooId/Put/Operation.Handler.cs

@@ -27,7 +27,7 @@ internal partial Task<Response> HandleAsync(Request request, CancellationToken c
         _ = request.Header.Bar;
 
         var response = new Response.OK200(Components.Schemas.FooProperties.Create(
-                name: request.Body.ApplicationJson?.Name))
+                name: request.Body.ApplicationJson?.Name), "application/json")
         {
             Headers = new Response.OK200.ResponseHeaders
             {

tests/Example.OpenApi32/openapi.json

@@ -48,7 +48,7 @@
               }
             },
             "content": {
-              "application/json": {
+              "application/*": {
                 "schema": {
                   "$ref": "#/components/schemas/FooProperties"
                 }