Make some operations exempt from app permissions. (#3851)

[afck]

Motivation

Chains with restricted block operations can't process e.g. new events because system operations are not allowed.

Proposal

Allow Process*Epoch regardless of permissions.

Test Plan

A test was extended.

Release Plan

• These changes should
  • be released in a new SDK,
  • be released in a validator hotfix.

Links

• Backport of part of https://github.com/linera-io/linera-protocol/pull/3851.
• reviewer checklist