gh-125449: Remove `PyUnicode_READY` function in `unicodeobject.h` #129083

Job	Run time
Change detection / Compute changed files	10s
Check if generated files are up to date	3m 34s
Windows MSI${{ '' }}	0s
Address sanitizer	9m 56s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.0.15)	2m 9s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.1.7)	2m 15s
CIFuzz (address)	20m 3s
Hypothesis tests on Ubuntu	5m 23s
CIFuzz (undefined)	21m 42s
CIFuzz (memory)	20m 29s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.2.3)	2m 8s
Ubuntu SSL tests with OpenSSL (ubuntu-22.04, 3.3.2)	2m 5s
Thread sanitizer / Thread sanitizer	4m 22s
Thread sanitizer (free-threading) / Thread sanitizer	7m 28s
WASI / build and test	6m 31s
macOS (free-threading) / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	14m 23s
macOS / build and test (ghcr.io/cirruslabs/macos-runner:sonoma)	5m 18s
macOS / build and test (macos-13)	9m 49s
Ubuntu / build and test (ubuntu-22.04)	7m 48s
Ubuntu (free-threading) / build and test (ubuntu-22.04)	10m 41s
Windows / build (arm64)	2m 55s
Windows (free-threading) / build (arm64)	3m 7s
Windows / build and test (Win32)	16m 19s
Windows (free-threading) / build and test (Win32)	23m 57s
Windows / build and test (x64)	15m 33s
Windows (free-threading) / build and test (x64)	23m 43s
Docs / Docs	1m 51s
Docs / Docs (Oldest Sphinx)	1m 48s
Docs / Doctest	18m 46s
All required checks pass	4s
	4h 24m 17s

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