Update ProxyUrlReplaceSettingsModel with TransformTemplate property (#1362)

* Update ProxyUrlReplaceSettingsModel with TransformTemplate property + parse settings correctly

* oldValue nullable

* <Version>1.14.0-preview-01</Version>

test/WireMock.Net.Tests/AdminApi/WireMockAdminApiTests.IWireMockAdminApi_GetMappingAsync_WithProxy_And_ProxyUrlReplaceSettings_And_TransformTemplate.verified.txt

@@ -0,0 +1,29 @@
+{
+  Guid: 90356dba-b36c-469a-a17e-669cd84f1f06,
+  UpdatedAt: DateTime_1,
+  Request: {
+    Path: {
+      Matchers: [
+        {
+          Name: WildcardMatcher,
+          Pattern: /1,
+          IgnoreCase: false
+        }
+      ]
+    },
+    Body: {
+      Matcher: {
+        Name: RegexMatcher,
+        Pattern: hello,
+        IgnoreCase: true
+      }
+    }
+  },
+  Response: {
+    ProxyUrl: https://my-proxy.com,
+    ProxyUrlReplaceSettings: {
+      IgnoreCase: false,
+      TransformTemplate: x{{this}}y
+    }
+  }
+}

test/WireMock.Net.Tests/AdminApi/WireMockAdminApiTests.cs

@@ -450,6 +450,55 @@ public partial class WireMockAdminApiTests
         server.Stop();
     }
 
+    [Fact]
+    public async Task IWireMockAdminApi_GetMappingAsync_WithProxy_And_ProxyUrlReplaceSettings_And_TransformTemplate()
+    {
+        // Arrange
+        var guid = Guid.Parse("90356dba-b36c-469a-a17e-669cd84f1f06");
+        var server = WireMockServer.StartWithAdminInterface();
+        var api = RestClient.For<IWireMockAdminApi>(server.Url);
+
+        // Act
+        var model = new MappingModel
+        {
+            Guid = guid,
+            Request = new RequestModel
+            {
+                Path = "/1",
+                Body = new BodyModel
+                {
+                    Matcher = new MatcherModel
+                    {
+                        Name = "RegexMatcher",
+                        Pattern = "hello",
+                        IgnoreCase = true
+                    }
+                }
+            },
+            Response = new ResponseModel
+            {
+                ProxyUrl = "https://my-proxy.com",
+                ProxyUrlReplaceSettings = new ProxyUrlReplaceSettingsModel
+                {
+                    TransformTemplate = "x{{this}}y"
+                }
+            }
+        };
+        var postMappingResult = await api.PostMappingAsync(model).ConfigureAwait(false);
+
+        // Assert
+        postMappingResult.Should().NotBeNull();
+
+        var mapping = server.Mappings.FirstOrDefault(m => m.Guid == guid);
+        mapping.Should().NotBeNull();
+
+        var getMappingResult = await api.GetMappingAsync(guid).ConfigureAwait(false);
+
+        await Verifier.Verify(getMappingResult, VerifySettings).DontScrubGuids();
+
+        server.Stop();
+    }
+
     [Fact]
     public async Task IWireMockAdminApi_GetRequestsAsync_Json()
     {