Allow deploying programs with only views (no functions)

[mohammadfawaz]

Follow-up from #3253.

check_program_is_well_formed currently requires at least one function, so a program declaring only views (and no functions) cannot be deployed today. Such deployments would have 0 verifying keys, which may violate downstream assumptions across the deploy/verify path.

Investigate the assumptions and, if safe, relax check_program_is_well_formed to accept view-only programs.