fix(typescript-axios): Correct the content type for a list of objects in form-data when contentType is present (#18505)

* fix content type for list of objects in form-data

* updated the samples

Author: Kavan72

modules/openapi-generator/src/main/resources/typescript-axios/apiInner.mustache

@@ -189,9 +189,14 @@ export const {{classname}}AxiosParamCreator = function (configuration?: Configur
             {{#isArray}}
             if ({{paramName}}) {
             {{#isCollectionFormatMulti}}
+              {{#contentType}}
+                localVarFormParams.append('{{baseName}}', new Blob([JSON.stringify({{paramName}})], { type: "{{contentType}}", }));
+              {{/contentType}}
+              {{^contentType}}
                 {{paramName}}.forEach((element) => {
-                    localVarFormParams.{{#multipartFormData}}append{{/multipartFormData}}{{^multipartFormData}}set{{/multipartFormData}}('{{baseName}}', element as any);
+                  localVarFormParams.{{#multipartFormData}}append{{/multipartFormData}}{{^multipartFormData}}set{{/multipartFormData}}('{{baseName}}', element as any);
                 })
+              {{/contentType}}
             {{/isCollectionFormatMulti}}
             {{^isCollectionFormatMulti}}
                 localVarFormParams.{{#multipartFormData}}append{{/multipartFormData}}{{^multipartFormData}}set{{/multipartFormData}}('{{baseName}}', {{paramName}}.join(COLLECTION_FORMATS.{{collectionFormat}}));

samples/client/echo_api/typescript-axios/build/api.ts

@@ -615,7 +615,7 @@ export const BodyApiAxiosParamCreator = function (configuration?: Configuration)
 
             if (files) {
                 files.forEach((element) => {
-                    localVarFormParams.append('files', element as any);
+                  localVarFormParams.append('files', element as any);
                 })
             }