Add logic to map primitives to simple types for types without format

Author: MaggieKimani1

src/Microsoft.OpenApi/Extensions/OpenApiTypeMapper.cs

@@ -100,9 +100,11 @@ public static Type MapOpenApiPrimitiveTypeToSimpleType(this OpenApiSchema schema
                 ("boolean", null, false) => typeof(bool),
                 ("integer", "int32", false) => typeof(int),
                 ("integer", "int64", false) => typeof(long),
+                ("integer", null, false) => typeof(int),
                 ("number", "float", false) => typeof(float),
-                ("number", "double", false) => typeof(double),
+                ("number", "double", false) => typeof(double),                
                 ("number", "decimal", false) => typeof(decimal),
+                ("number", null, false) => typeof(double),
                 ("string", "byte", false) => typeof(byte),
                 ("string", "date-time", false) => typeof(DateTimeOffset),
                 ("string", "uuid", false) => typeof(Guid),
@@ -113,8 +115,10 @@ public static Type MapOpenApiPrimitiveTypeToSimpleType(this OpenApiSchema schema
                 ("string", "uri", false) => typeof(Uri),
                 ("integer", "int32", true) => typeof(int?),
                 ("integer", "int64", true) => typeof(long?),
+                ("integer", null, true) => typeof(int),
                 ("number", "float", true) => typeof(float?),
                 ("number", "double", true) => typeof(double?),
+                ("number", null, true) => typeof(double),
                 ("number", "decimal", true) => typeof(decimal?),
                 ("string", "byte", true) => typeof(byte?),
                 ("string", "date-time", true) => typeof(DateTimeOffset?),