HAWK Authentication uses wrong content type for graphql requests

### Expected Behavior

Authentication process should pass on server.
Insomnia should use `content-type` header for payload hash computation

### Actual Behavior

Authentication process fails due to wrong content type used by insomnia for hash computation

### Reproduction Steps

1) Make a GraphQL Request with HAWK Authentication
2) Obviously it will use by default `content-type: application/json` in headers section
3) Send a request
4) Authentication fails even though HAWK's auth id and key are correct

I've debugged it in dev tools and turned out that insomnia ignores `content-type` header and uses `body.mimeType` instead which will be `application/graphql` in case of graphql requests.

Repository: https://github.com/wookieb/insomnia-issue-4855

### Is there an existing issue for this?

- [X] I have searched the [issue tracker](https://www.github.com/Kong/insomnia/issues) for this problem.

### Additional Information

You're using `@hapi/hawk`but this is no longer maintained. You should upgrade to `hawk`

I wanted to fix it on my own but apparently this part of code is nor available in this repository?

### Insomnia Version

2022.3.0

### What operating system are you using?

macOS

### Operating System Version

OSX 12.4

### Installation method

insomnia.rest

### Last Known Working Insomnia version

_No response_

No source file or test is named in the issue. Start by locating the HAWK authentication request-signing entry point and the GraphQL request body/content-type handling, then reproduce the failure with a GraphQL request that sends content-type: application/json. Done means the signing process uses the request header consistently and authentication succeeds with the reported request.

Written by the indexing model from the issue text.