fix: use issue.node_id for permit nonces

[rndquu]

Resolves ubiquity-os/permit-generation#46

QA (development branch, old buggy behavior):
rndquu-org/my-repo-1#1 (comment): nonce=78893650957373058525222459826056873078870981337600027323707876018366845390587
rndquu-org/my-repo-2#1 (comment): nonce=78893650957373058525222459826056873078870981337600027323707876018366845390587

QA (fix/nonce-generation branch):
rndquu-org/my-repo-1#1 (comment): nonce=47174999346132534354494673705511461942918468951327270802916300108996236752932
rndquu-org/my-repo-2#1 (comment): nonce=83029153680898263555035957871388564685254995512260384748899620589901226451761

In the 1st case (QA for development branch) nonces are the same because issue number is used for nonce generation (not issue.id or issue.node_id). Hence 2 issues with the same issue number across 2 different repositories have equal nonces.

In the 2nd case (QA for fix/nonce-generation branch) we use issue.node_id for nonce generation which is different for any 2 repositories we take.

Notes:

• Here here we still use issue number in order not to break saving permits (in particular saving data to the locations table). When we're about to remove the deprecated locations table then issue number related logic can be removed as well.
• Tests are updated because nonce is calculated using issue.node_id instead of issue number hence permit URLs changed
• Test timeout is increased because of this failing CI run (Exceeded timeout of 10000 ms for a test)

[0x4007]

Let's always use latest. Otherwise looks good to me.