The Bug
This works both inside and outside of water. It doesn't actually do anything (except showing some fancy particles), even though the bone meal is used up if you are in survival mode.
Steps to Reproduce
Place down a singular sea pickle on some dry land.
Obtain some bone meal and apply several amounts of it to the sea pickle.
Take note as to whether or not you can apply bone meal to sea pickles in situations where they cannot grow.
Observed Behavior
You can apply bone meal to sea pickles in situations where they cannot grow.
Expected Behavior
You would not be able to apply bone meal to sea pickles in situations where they cannot grow.
Code Analysis
Code analysis by @unknown can be found in this comment.
They actually will grow, but only when they're on coral, and only inside water. Might want to add that to the issue, as bone meal shouldn't be able to be used outside of those conditions.
EDIT: They can also be grown inside flowing water, which is probably also a bug.