task/SWTCH-1527 change selfsigned claim payload to arbitrary object

[JGiter]

BREAKING CHANGE: Payload of selfsigned claim is arbitrary object

Description

Contributor checklist

• [x] Breaking changes - check for any existing interfaces changes that are not backward compatible, removed method etc.
• [x] Documentation - document your code, add comments for method, remember to check if auto generated docs were updated.
• [x] Tests - add new or updated existed test for changes you made.
• [x] Migration guide - add migration guide for every breaking change.
• [x] Configuration correctness - check that any configuration changes are correct ex. default URLs, chain ids, smart contract verification on Volta explorer or EWC explorer.

[ewf-devops]

:tada: This PR is included in version 7.0.0-alpha.1 :tada:

The release is available on:

• npm package (@canary dist-tag)
• GitHub release

Your semantic-release bot :package::rocket:

[ewf-devops]

:tada: This PR is included in version 7.0.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: