bug: cameras inconsistently appearing in QGC

### Bug description

Brought up in [this forum post](https://discuss.bluerobotics.com/t/disable-automatic-video-display-on-qgroundcontrol/12109):

> QGroundControl with BlueOS will automatically display the video streams ... [but] the video changing function is not very reliable and having 3 cameras on our setup, most of the time only 1 or 2 show up and its inconsistent with which camera shows and which don’t.

### Steps to reproduce

1. Start multiple streams in BlueOS
2. Check QGC for available ones
3. Repeat with inconsistent results [NEEDS CONFIRMATION]

### Primary pain point(s)

Makes it harder to effectively use multiple cameras with BlueOS, and encourages using external applications for streaming any/all video instead of QGC (which fragments the user experience).

### Prerequisites

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