Is your feature request related to a problem? Please describe.
Right clicking a backpack on the ground will put the back pack on if:

1. your hand is empty and
2. you have no shield equipped

Describe the solution you'd like
Backpack is picked up and worn when right clicked regardless if you have a shield equipped.

Additionally (nice to have), if you are wearing backpack and right click a backpack on the ground it would be nice to be able to swap the backpacks.

Describe alternatives you've considered
n/a

Additional context
n/a

Backpack can be picked up with any item in hand now
I didnt add swapping backpack feature

https://www.curseforge.com/minecraft/mc-mods/travelers-backpack-fabric/files/all
Available for Fabric
(Forge soon)

https://www.curseforge.com/minecraft/mc-mods/travelers-backpack/files