Remove unused wireless packages

[emkll]

Status

Ready for review

Description of Changes

Fixes #4163

Testing

Clean install scenario:

• Xenial staging tests pass
• Nightly Trusty tests pass

Upgrade testing scenario (requires prod VMs or hardware)

• Install on 0.12.0 (on 0.12.0 tag)
• Upgrade to Xenial
• Run install on this branch
• Observe wireless packages are removed

Deployment

This change to the Ansible logic will be deployed via GitHub, and deployed to server when an admin installs.

Checklist

If you made changes to the system configuration:

• Configuration tests pass

If you made non-trivial code changes:

• I have written a test plan and validated it for this PR

[conorsch]

Performed manual testing of the upgrade scenario. For the staging test plan, I'm relying on CI to confirm working, after visual review of the logic.

Clean install scenario:

• Xenial staging tests pass - https://circleci.com/gh/freedomofpress/securedrop/23981
• 🔶 Nightly Trusty tests pass (have not confirmed in CI yet, we'll watch after this lands in develop)

Upgrade testing scenario (requires prod VMs or hardware)

• Install on 0.12.0 (on 0.12.0 tag)
• Upgrade to Xenial
• Run install on this branch
• Observe wireless packages are removed

During prod VM testing, after installing from 0.12.0, I upgraded only app-prod to 16.04, then re-ran the install action on this feature branch. During the install run, confirmed that Ansible reported the package removal on both hosts, regardless of Trusty or Xenial. Additionally, confirmed via interactive login that the three (3) packages were not installed on both hosts.