Unable to directly feed cakes to pandas

Summary: You are unable to right-click a cake on a panda to feed it.

How to reproduce:

1. Summon a panda and get a cake.
2. Attempt to directly feed the panda cake by right-clicking on it.

Notes: For whatever reason, this is not the case with bamboo, as you can still right-click bamboo on a panda to feed/breed it. Dropping a cake also allows the panda to eat the cake, which creates another bug (MC-234063).