BUG: plugin_allowlist accepts garbage input without error

[Ryanf55]

Expected Behavior

If you request plugins to load that don't exist, mavros should either print an error. Same for denylist.

Actual behavior

No error is emitted, a garbage plugin name is silently discarded. This results in a typo in a plugin name resulting in not loading what you expect.

/**:
  ros__parameters:
    plugin_allowlist:
       - 'sys_status'
       - 'sys_time'
       - 'garbage'

$ ros2 param dump /mavros/mavros
/mavros/mavros:
  ros__parameters:
    base_link_frame_id: base_link
    component_id: 191
    diagnostic_updater:
      period: 1.0
      use_fqn: false
    fcu_protocol: v2.0
    map_frame_id: map
    odom_frame_id: odom
    plugin_allowlist:
    - sys_status
    - sys_time
    - garbage

Simply, in CLI:

ros2 run mavros mavros_node --ros-args -p plugin_allowlist:=['foobar']