Detect JSON API content type ('application/vnd.api+json') as textual content (#2337)

Summary:
Network requests and responses using JSON API content type of pattern `application/vnd.api+json` (see https://jsonapi.org/#mime-types) are currently treated as binary data. They should be treated as textual content.

## Changelog

Add regular expression to detect JSON content types.

Pull Request resolved: https://github.com/facebook/flipper/pull/2337

Test Plan: Using an API that return `Content-Type` of pattern `application/vnd.api+json`, verify that the response data in sidebar appears as text rather than `(binary data)`.

Reviewed By: passy

Differential Revision: D28513547

Pulled By: mweststrate

fbshipit-source-id: 3335b7eeb63c2429c2245113c8c83bd7e08a9420

desktop/plugins/public/network/utils.tsx

@@ -26,6 +26,9 @@ export function getHeaderValue(
   return '';
 }
 
+// Matches `application/json` and `application/vnd.api.v42+json` (see https://jsonapi.org/#mime-types)
+const jsonContentTypeRegex = new RegExp('application/(json|.+\\+json)');
+
 export function isTextual(headers?: Array<Header>): boolean {
   const contentType = getHeaderValue(headers, 'Content-Type');
   if (!contentType) {
@@ -36,7 +39,7 @@ export function isTextual(headers?: Array<Header>): boolean {
   return (
     contentType.startsWith('text/') ||
     contentType.startsWith('application/x-www-form-urlencoded') ||
-    contentType.startsWith('application/json') ||
+    jsonContentTypeRegex.test(contentType) ||
     contentType.startsWith('multipart/') ||
     contentType.startsWith('message/') ||
     contentType.startsWith('image/svg') ||