storage_controller: make address for peers mandatory

[VladLazar]

Problem

address-for-peers is now used everywhere (TODO: apart from cplane set-up)).

Summary of changes

Make the config mandatory

[github-actions]

No tests were run or test report is not available

Test coverage report is not available

_{The comment gets automatically updated with the latest test results
7e569b9 at 2025-04-24T15:19:24.635Z :recycle:}