ICU-22575 Change AvailableFormatsSink to allow locales to inherit ava… #1259

Job	Run time
clang-valgrind-test	10m 24s
clang-valgrind-intltest (utility)	6m 35s
clang-valgrind-intltest (normalize)	6m 12s
clang-valgrind-intltest (collator)	5m 11s
clang-valgrind-intltest (regex)	5m 5s
clang-valgrind-intltest (format)	16m 31s
clang-valgrind-intltest (translit)	6m 1s
clang-valgrind-intltest (rbbi)	7m 1s
clang-valgrind-intltest (rbnf)	6m 25s
clang-valgrind-intltest (rbnfrt)	6m 19s
clang-valgrind-intltest (icuserv)	5m 3s
clang-valgrind-intltest (idna)	5m 4s
clang-valgrind-intltest (convert)	6m 52s
clang-valgrind-intltest (rbnfp)	5m 32s
clang-valgrind-intltest (csdet)	5m 9s
clang-valgrind-intltest (spoof)	5m 4s
clang-valgrind-intltest (bidi)	5m 15s
	1h 53m 43s

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