Fix logic to parse JSON responses in Form wrapper

[ayushn21]

When using the form wrapper, there's a mechanism to process JSON encoded responses, but this won't work if the content-type header isn't EXACTLY application/json. It can sometimes be application/json; charset=UTF8 or something like that.

This change splits the string on the ; and uses the first part to lookup the parser.

I'm not sure what the best way to test this is though.

Types of Changes

• Bug fix.

Contribution

• I added tests for my changes.
• I tested my changes locally.
• I agree to the Developer's Certificate of Origin 1.1.

[ioquatix]

The part before the ; is referred to as the media type. On the surface, this looks okay to me, but I'll consider if there are bigger implications.