Context

The challenge code is always hardcoded when mockserver feature is activated: https://github.com/litentry/litentry-parachain/blob/c485920fbdc980fcf0a8aac1ace9011c6606c8d1/tee-worker/app-libs/stf/src/helpers.rs#L134-L141

This makes it impossible to test e.g. #981, where we want to explicitly check the update of challenge code.

We need to either:

• remove the hardcoded challenge code, and make mockserver to read the challenge code live from the chain state
  or
• still use hardcoded but make it different each time, e.g. calculated from some outside inputs (env/command line/....)

And generally I'm not a fan ofmockserver feature as it requires a re-compilation and makes the test switch between dev/staging hard. Can we somehow remove this feature and use unified codebase? E.g. fully controlled by command line or startup args for worker.

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