fix(automate): fix possible auth error

[cdriesler]

Description & motivation

• Deep diving into automate auth for ongoing work, appear to have caught a bug
• The final part of the handshake - where automate asks speckle server if the auth code is real and valid:
  • Correctly checks if the code exists at all
  • Appears to be incorrectly asserting specific claims (user id, action) against itself, instead of the code automate has

Changes:

• Validate stored auth code against incoming auth code from automate server, instead of itself (appears to be the intent of the code)

[iainsproat]

No need to publish a security bulletin to advise self-servers to upgrade, as they could not enable Automate and this code anyway.