[Typescript-jQuery] Fix for issue #6505 (#6541)

* Fix that prevented the default version to generate the model files

* Add generated samples

Author: JFCote

modules/swagger-codegen/src/main/resources/typescript-jquery/api.mustache

@@ -103,7 +103,7 @@ export class {{classname}} {
 {{#formParams}}
 {{#isFile}}
         reqHasFile = true;
-        formParams = {{paramName}};
+        formParams.append("{{baseName}}", {{paramName}});
 {{/isFile}}
 {{^isFile}}
         {{#isListContainer}}