OSV-2023-905 Segv on unknown address in icu_74::UnicodeString::copyFrom

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=62651 Crash type: Segv on unknown address Crash state: icu74::UnicodeString::copyFrom icu74::UnicodeString::UnicodeString icu74::number::impl::SimpleModifier::SimpleModifier...