fix build with icu 78

from https://hg-edge.mozilla.org/mozilla-central/rev/5b1712d5d0a3
remove in 147
Index: intl/lwbrk/LineBreaker.cpp
--- intl/lwbrk/LineBreaker.cpp.orig
+++ intl/lwbrk/LineBreaker.cpp
@@ -453,6 +453,7 @@ static int8_t GetClass(uint32_t u, LineBreakRule aLeve
       /* AKSARA_START = 45,                 [AS] */ CLASS_CHARACTER,
       /* VIRAMA_FINAL = 46,                 [VF] */ CLASS_CHARACTER,
       /* VIRAMA = 47,                       [VI] */ CLASS_CHARACTER,
+      /* UNAMBIGUOUS_HYPHEN = 48            [HH] */ CLASS_BREAKABLE,
   };
 
   static_assert(U_LB_COUNT == std::size(sUnicodeLineBreakToClass),
