refactor: drop use of behavior in recursively_apply

[agoose77]

This prepares the way to drop this argument in recursively_apply

[jpivarski]

When string-broadcasting was hard-coded, no longer derived from a behavior, we no longer needed to pass behaviors into broadcast_and_apply, and I suppose it was being passed into recursively_apply for symmetry.

If the tests pass after simply removing it like this, then I suppose nothing was using it. I would have expected it to be passed to the action function, but apparently it's not.

Actually, why are these changes only in ak.operations.str.*? We use recursively_apply in a lot of places, not just here. Why don't they all have behavior=behavior push-downs to remove? Was this never really a part of the recursively_apply interface and their use in string functions was a mistake?

Anyway, I'm in favor of removing behavior from recursively_apply. It doesn't even mean we can't use it in recursively_apply's action functions, since the action function can be defined in such a way as to close over that variable. So, please do make the end-state of this to be such that behavior is removed from the recursively_apply interface, whether that involves changes beyond ak.operations.str.* or not.

[codecov]

Codecov Report

Merging #2805 (ff3ef68) into main (aafd2b4) will decrease coverage by 0.01%.
The diff coverage is 96.61%.

Additional details and impacted files

Files	Coverage Δ
src/awkward/_do.py	83.43% <ø> (ø)
src/awkward/contents/bitmaskedarray.py	69.57% <100.00%> (ø)
src/awkward/contents/bytemaskedarray.py	89.10% <100.00%> (ø)
src/awkward/contents/emptyarray.py	75.24% <100.00%> (ø)
src/awkward/contents/indexedarray.py	79.04% <100.00%> (ø)
src/awkward/contents/indexedoptionarray.py	88.52% <100.00%> (ø)
src/awkward/contents/listarray.py	88.40% <100.00%> (ø)
src/awkward/contents/listoffsetarray.py	82.80% <100.00%> (ø)
src/awkward/contents/numpyarray.py	91.23% <100.00%> (ø)
src/awkward/contents/recordarray.py	84.58% <100.00%> (ø)
... and 73 more

[agoose77]

Actually, why are these changes only in ak.operations.str.*? We use recursively_apply in a lot of places, not just here. Why don't they all have behavior=behavior push-downs to remove? Was this never really a part of the recursively_apply interface and their use in string functions was a mistake?

I was originally going to just start with ak.str, and follow up, as this PR was cherry-picked from another. However, let's just do it all together.