firewall: T7112: Default action drop fails

[alexandr-san4ez]

Change summary

Prevent KeyError by safely handling missing 'member' dict in zone config.
Add smoketest to verify commit fails gracefully when zone has no interfaces.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T7112

Manual test

vyos@vyos:~$ conf
vyos@vyos# set firewall zone wan default-action drop
vyos@vyos# commit
[ firewall ]
Zone "wan" has no interfaces and is not the local zone
[[firewall]] failed
Commit failed

Smoketest

$ /usr/libexec/vyos/tests/smoke/cli/test_firewall.py
...
test_zone_basic (__main__.TestFirewall.test_zone_basic) ... ok
test_zone_flow_offload (__main__.TestFirewall.test_zone_flow_offload) ... ok
test_zone_with_vrf (__main__.TestFirewall.test_zone_with_vrf) ... ok
test_zone_without_member (__main__.TestFirewall.test_zone_without_member) ... ok
...

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[github-actions]

👍
No issues in PR Title / Commit Title

[github-actions]

CI integration ❌ failed!

Details

CI logs

• CLI Smoketests (no interfaces) ❌ failed
• CLI Smoketests VPP 👍 passed
• CLI Smoketests (interfaces only) 👍 passed
• Config tests 👍 passed
• Config tests VPP 👍 passed
• RAID1 tests 👍 passed
• TPM tests 👍 passed

[sarthurdev]

Fixes KeyError if member not defined. Code looks good and includes smoketest (passes).

[sever-sever]

Do not allow the use of action without an interface if it is not local zone