BUG: Add fillna at the beginning of _where not to fill NA. #60729 #22637

Job	Run time
Linux-32-bit	18m 36s
Linux-Musl	16m 35s
python-freethreading	24m 19s
python-dev (macOS-13)	19m 37s
python-dev (macOS-14)	9m 40s
python-dev (ubuntu-22.04)	20m 11s
python-dev (windows-latest)	22m 11s
Pyodide build	23m 10s
Minimum Versions	25m 11s
Future infer strings (without pyarrow)	56m 15s
Locale: zh_CN	39m 8s
Locale: it_IT	38m 18s
Downstream Compat	6m 41s
Numpy Dev	17m 4s
Pyarrow Nightly	21m 31s
Future infer strings	1h 4m 54s
Pypy	1m 39s
ubuntu-22.04 actions-310.yaml	1h 4m 44s
ubuntu-22.04 actions-311.yaml	58m 47s
ubuntu-22.04 actions-312.yaml	1h 4m 10s
ubuntu-24.04-arm actions-311.yaml	36m 6s
ubuntu-24.04-arm actions-312.yaml	39m 52s
ubuntu-24.04-arm actions-310.yaml	36m 31s
macos-13 actions-310.yaml	52m 13s
macos-13 actions-311.yaml	53m 37s
macos-13 actions-312.yaml	43m 7s
macos-14 actions-310.yaml	28m 9s
macos-14 actions-311.yaml	25m 48s
macos-14 actions-312.yaml	21m 30s
windows-latest actions-311.yaml	51m 14s
windows-latest actions-312.yaml	1h 6m 27s
windows-latest actions-310.yaml	50m 36s
	18h 37m 51s

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