chore: adds unit tests for headers reference inlining

Signed-off-by: Vincent Biret <vibiret@microsoft.com>

Author: baywet

test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeCallbackReferenceAsV3JsonWorks_produceTerseOutput=True.verified.txt

@@ -0,0 +1,3 @@
+{
+  "$ref": "#/headers/LocationHeader"
+}

test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeHeaderReferenceAsV2JsonWorksAsync_produceTerseOutput=False.verified.txt

@@ -1,6 +1,4 @@
 {
   "description": "The URL of the newly created post",
-  "schema": {
-    "type": "string"
-  }
+  "type": "string"
 }

test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeHeaderReferenceAsV2JsonWorksAsync_produceTerseOutput=False_inlineLocalReferences=False.verified.txt

@@ -0,0 +1 @@
+{"$ref":"#/headers/LocationHeader"}

…ks_produceTerseOutput=False.verified.txt …_inlineLocalReferences=True.verified.txttest/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeCallbackReferenceAsV3JsonWorks_produceTerseOutput=False.verified.txt renamed to test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeHeaderReferenceAsV2JsonWorksAsync_produceTerseOutput=False_inlineLocalReferences=True.verified.txt test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeCallbackReferenceAsV3JsonWorks_produceTerseOutput=False.verified.txt renamed to test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeHeaderReferenceAsV2JsonWorksAsync_produceTerseOutput=False_inlineLocalReferences=True.verified.txt

@@ -0,0 +1 @@
+{"description":"The URL of the newly created post","type":"string"}

test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeHeaderReferenceAsV2JsonWorksAsync_produceTerseOutput=True.verified.txt

@@ -1,6 +1,4 @@
 {
   "description": "Location of the locally referenced post",
-  "schema": {
-    "type": "string"
-  }
+  "$ref": "#/components/headers/LocationHeader"
 }

test/Microsoft.OpenApi.Tests/Models/References/OpenApiHeaderReferenceTests.SerializeHeaderReferenceAsV2JsonWorksAsync_produceTerseOutput=True_inlineLocalReferences=False.verified.txt

@@ -0,0 +1 @@
+{"description":"Location of the locally referenced post","$ref":"#/components/headers/LocationHeader"}