fix(issue_cache): add pull-requests to cache

[fruch]

in some places we are using PRs and not issue to identify if we should be skipping something in the test code

for that we are now scannning diffrently the issue, with the usage of graphql and github search

Ref: scylladb/qa-tasks#1735

Testing

• [ ]

PR pre-checks (self review)

• I added the relevant backport labels
• I didn't leave commented-out/debugging code

Reminders

• Add New configuration option and document them (in sdcm/sct_config.py)
• Add unit tests to cover my changes (under unit-test/ folder)
• Update the Readme/doc folder relevant to this change (if needed)