ICU-22575 Change AvailableFormatsSink to allow locales to inherit ava… #1215

Job	Run time
clang-valgrind-test	10m 1s
clang-valgrind-intltest (utility)	6m 32s
clang-valgrind-intltest (normalize)	5m 59s
clang-valgrind-intltest (collator)	5m 12s
clang-valgrind-intltest (regex)	5m 9s
clang-valgrind-intltest (format)	16m 26s
clang-valgrind-intltest (translit)	5m 55s
clang-valgrind-intltest (rbbi)	7m 17s
clang-valgrind-intltest (rbnf)	6m 8s
clang-valgrind-intltest (rbnfrt)	6m 3s
clang-valgrind-intltest (icuserv)	4m 55s
clang-valgrind-intltest (idna)	5m 9s
clang-valgrind-intltest (convert)	6m 20s
clang-valgrind-intltest (rbnfp)	4m 55s
clang-valgrind-intltest (csdet)	5m 1s
clang-valgrind-intltest (spoof)	5m 3s
clang-valgrind-intltest (bidi)	4m 58s
	1h 51m 3s

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