SCORU,node: check that the operator is in the whitelist at startup

Context

Check that the operator in publish mode can commit at rollup node startup iff the rollup is public or the operator (in operating mode) is in the whitelist.

Manually testing the MR

dune exec tezt/tests/main.exe -- --file sc_rollup.ml "whitelist"

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR