Fix tests

Author: RicoSuter

src/NSwag.ConsoleCore.Tests/GenerateSampleSpecificationTests.CheckCSharpClientsAsync_projectName=NSwag.Sample.NET70Minimal_targetFramework=net7.0_generatesCode=True.verified.txt

@@ -258,7 +258,9 @@ namespace MyNamespace
                     var disposeResponse_ = true;
                     try
                     {
-                        var headers_ = System.Linq.Enumerable.ToDictionary(response_.Headers, h_ => h_.Key, h_ => h_.Value);
+                        var headers_ = new System.Collections.Generic.Dictionary<string, System.Collections.Generic.IEnumerable<string>>();
+                        foreach (var item_ in response_.Headers)
+                            headers_[item_.Key] = item_.Value;
                         if (response_.Content != null && response_.Content.Headers != null)
                         {
                             foreach (var item_ in response_.Content.Headers)

src/NSwag.Sample.NET70Minimal/GeneratedClientsCs.gen

@@ -258,7 +258,9 @@ namespace MyNamespace
                     var disposeResponse_ = true;
                     try
                     {
-                        var headers_ = System.Linq.Enumerable.ToDictionary(response_.Headers, h_ => h_.Key, h_ => h_.Value);
+                        var headers_ = new System.Collections.Generic.Dictionary<string, System.Collections.Generic.IEnumerable<string>>();
+                        foreach (var item_ in response_.Headers)
+                            headers_[item_.Key] = item_.Value;
                         if (response_.Content != null && response_.Content.Headers != null)
                         {
                             foreach (var item_ in response_.Content.Headers)

src/NSwag.Sample.NET70Minimal/nswag.json

@@ -83,7 +83,9 @@
       "clientBaseClass": null,
       "configurationClass": null,
       "generateClientClasses": true,
+      "suppressClientClassesOutput": false,
       "generateClientInterfaces": false,
+      "suppressClientInterfacesOutput": false,
       "clientBaseInterface": null,
       "injectHttpClient": true,
       "disposeHttpClient": true,