Checking if encodedDetails can be decoded in the parse function

[MarkusGarmeister]

fixes KILTProtocol/ticket#3033

A light DID resolution with encoded details, which can not be decoded, is parsed and decoded twice. I tried to fix this with a check of the encodedDetails in the parse function. However the tests are failling.

Checklist:

• [ ] I have verified that the code works
• [ ] I have verified that the code is easy to understand
  • [ ] If not, I have left a well-balanced amount of inline comments
• [ ] I have left the code in a better state
• [x] I have documented the changes (where applicable)
  • Either PR or Ticket to update the Docs
  • Link the PR/Ticket here