typescript-fetch: Move parenthesis to correct place (#18075)

A misplaced parenthesis let to a syntax error when generating the code for a nullable set in the FromJSONTyped function. By moving the parenthesis to the correct place the syntax error was resolved.

modules/openapi-generator/src/main/resources/typescript-fetch/modelGeneric.mustache

@@ -72,7 +72,7 @@ export function {{classname}}FromJSONTyped(json: any, ignoreDiscriminator: boole
         {{^isPrimitiveType}}
         {{#isArray}}
         {{#uniqueItems}}
-        '{{name}}': {{^required}}json['{{baseName}}'] == null ? undefined : {{/required}}{{#required}}({{#isNullable}}json['{{baseName}}'] == null ? null : {{/isNullable}}{{/required}}new Set((json['{{baseName}}'] as Array<any>).map({{#items}}{{datatype}}{{/items}}FromJSON))),
+        '{{name}}': {{^required}}json['{{baseName}}'] == null ? undefined : {{/required}}({{#required}}{{#isNullable}}json['{{baseName}}'] == null ? null : {{/isNullable}}{{/required}}new Set((json['{{baseName}}'] as Array<any>).map({{#items}}{{datatype}}{{/items}}FromJSON))),
         {{/uniqueItems}}
         {{^uniqueItems}}
         '{{name}}': {{^required}}json['{{baseName}}'] == null ? undefined : {{/required}}({{#required}}{{#isNullable}}json['{{baseName}}'] == null ? null : {{/isNullable}}{{/required}}(json['{{baseName}}'] as Array<any>).map({{#items}}{{datatype}}{{/items}}FromJSON)),