fix(typescript-axios): Serialize boolean to string in form-data file upload (#18084)

Author: dvacca-onfido

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

@@ -199,8 +199,9 @@ export const {{classname}}AxiosParamCreator = function (configuration?: Configur
             }{{/isArray}}
             {{^isArray}}
             if ({{paramName}} !== undefined) { {{^multipartFormData}}
-                localVarFormParams.set('{{baseName}}', {{paramName}} as any);{{/multipartFormData}}{{#multipartFormData}}{{#isPrimitiveType}}
-                localVarFormParams.append('{{baseName}}', {{paramName}} as any);{{/isPrimitiveType}}{{^isPrimitiveType}}{{#isEnumRef}}
+                localVarFormParams.set('{{baseName}}', {{paramName}} as any);{{/multipartFormData}}{{#multipartFormData}}{{#isPrimitiveType}}{{^isBoolean}}
+                localVarFormParams.append('{{baseName}}', {{paramName}} as any);{{/isBoolean}}{{/isPrimitiveType}}{{#isPrimitiveType}}{{#isBoolean}}
+                localVarFormParams.append('{{baseName}}', String({{paramName}}) as any);{{/isBoolean}}{{/isPrimitiveType}}{{^isPrimitiveType}}{{#isEnumRef}}
                 localVarFormParams.append('{{baseName}}', {{paramName}} as any);{{/isEnumRef}}{{^isEnumRef}}
                 localVarFormParams.append('{{baseName}}', new Blob([JSON.stringify({{paramName}})], { type: "application/json", }));{{/isEnumRef}}{{/isPrimitiveType}}{{/multipartFormData}}
             }{{/isArray}}