[backport 2.3.x] API(str dtype): Raise on StringDtype for unary op + (#60710) #21545

Job	Run time
Linux-Musl	22m 4s
python-dev (macOS-13)	34m 24s
Linux-32-bit	19m 51s
python-dev (macOS-14)	16m 32s
python-dev (ubuntu-22.04)	26m 20s
python-dev (windows-latest)	28m 36s
macos-13 actions-310.yaml	49m 16s
macos-13 actions-311.yaml	41m 39s
macos-13 actions-312.yaml	44m 7s
macos-13 actions-39.yaml	45m 29s
macos-14 actions-310.yaml	25m 29s
macos-14 actions-311.yaml	18m 17s
macos-14 actions-312.yaml	25m 16s
macos-14 actions-39.yaml	31m 6s
windows-latest actions-311.yaml	44m 7s
windows-latest actions-312.yaml	48m 5s
windows-latest actions-39.yaml	38m 59s
windows-latest actions-310.yaml	37m 29s
ubuntu-latest actions-310.yaml	54m 13s
Copy-on-Write 3.10	28m 12s
ubuntu-latest actions-311.yaml	49m 38s
Future infer strings (without pyarrow)	50m 58s
Copy-on-Write 3.11	27m 10s
Locale: zh_CN	27m 17s
Copy-on-Write 3.11 (warnings)	27m 15s
Locale: it_IT	27m 11s
Downstream Compat	5m 42s
Numpy Dev	22m 6s
Pyarrow Nightly	25m 14s
ubuntu-latest actions-312.yaml	39m 38s
Future infer strings	39m 17s
Copy-on-Write 3.12	30m 35s
ubuntu-latest actions-39.yaml	49m 49s
Copy-on-Write 3.9 (warnings)	28m 23s
Copy-on-Write 3.9	28m 33s
Minimum Versions	28m 20s
Pypy	7m 47s
Copy-on-Write 3.10 (warnings)	29m 50s
	20h 24m 14s

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