bug: PX4 flight controller is not detected

### Bug description

`board_identification.identifiers` has no PX4 USB strings (`PX4`, `PX4 BL`). Autopilot manager only sees SITL.

### Steps to reproduce

1. Connect a PX4 Pixhawk over USB
2. Open Autopilot

### Primary pain point(s)

Board is ignored. Log ends on `Only available board is SITL`.

### Additional context

https://discuss.bluerobotics.com/t/blueos-1-4-2-cannot-detect-the-flightcontroller-px4/22027

### Prerequisites

- [x] I have checked to make sure that a similar request has not already been filed or fixed.

Start with board_identification.identifiers and the Autopilot manager path that currently reports "Only available board is SITL." Reproduce with a PX4 Pixhawk connected over USB, then verify that the board is detected and no longer ignored when the Autopilot view is opened.

Written by the indexing model from the issue text.