PX4 Subscribes to Trajectory Setpoint from Offboard Mode During RTL

[adk4davsys]

Describe the bug
Triggering RTL when publishing to trajectory_setpoint topic in Offboard Mode vehicle continues to subscribe to the topic and makes vehicle unstable.

To Reproduce
Steps to reproduce the behavior:

1. Publish to /fmu/trajectory_setpoint/in within Offboard Mode
2. Trigger RTL
3. Vehicle attempts to RTL while still setting position setpoint using the topic /fmu/trajectory_setpoint/in
4. Eventually vehicle returns to home but does not disarm and continues to point toward /fmu/trajectory_setpoint/in

Expected behavior
My understanding is that triggering RTL should ignore /fmu/trajectory_setpoint/in from Offboard Mode. Shown below are the comparison between publishing to /fmu/trajectory_setpoint/in and not publishing to the topic during RTL.

Log Files and Screenshots

Drone (please complete the following information):

• Based on V1.12.3
• Pixhawk 4

**Additional Context
This behavior was identified from issue #18983

[benjinne]

Currently there's a bug with trajectory_setpoint being published by both offboard and flight_tasks I fixed it in this PR #18318 but it's still waiting review

[adk4davsys]

@benjinne Thank you for following up on this issue. For the time being, I only publish to the topic while the copter is in offboard mode.