Compilation warnings for AP_DroneCAN - narrowing conversion

[Ryanf55]

Bug report

Issue details

Compilation warnings/errors have been introduced in AP_DroneCAN from a narrowing conversion.

Version
Master hash 64292958694d532b6bb92d6c8ea7c5210fc5c5a1

Platform
[x] All
[ ] AntennaTracker
[ ] Copter
[ ] Plane
[ ] Rover
[ ] Submarine

Airframe type
What type of airframe (flying wing, glider, hex, Y6, octa etc)

Hardware type
What autopilot hardware was used? (Pixhawk, Cube, Pixracer, Navio2, etc)

Logs

$ rm -r build
$ colcon build
../../libraries/AP_DroneCAN/AP_Canard_iface.cpp: In member function ‘virtual bool CanardInterface::broadcast(const Canard::Transfer&)’:
../../libraries/AP_DroneCAN/AP_Canard_iface.cpp:64:39: error: narrowing conversion of ‘(uint32_t)bcast_transfer.Canard::Transfer::payload_len’ from ‘uint32_t’ {aka ‘unsigned int’} to ‘uint16_t’ {aka ‘short unsigned int’} [-Werror=narrowing]
   64 |         .payload_len = bcast_transfer.payload_len,
      |                        ~~~~~~~~~~~~~~~^~~~~~~~~~~
compilation terminated due to -Wfatal-errors.
cc1plus: some warnings being treated as errors

[Ryanf55]

@bugobliterator Would you be able to issue a fix for this? The blame shows this was introduced in commit: 0c72897