fix(telegram): guard UTF-16 surrogate pairs in outbound chunkers (#93938)

Merged via squash.

Prepared head SHA: 583b22354d
Co-authored-by: Nas01010101 <156536069+Nas01010101@users.noreply.github.com>
Co-authored-by: vincentkoc <25068+vincentkoc@users.noreply.github.com>
Reviewed-by: @vincentkoc

src/shared/text-chunking.ts

@@ -16,7 +16,7 @@ export function avoidTrailingHighSurrogateBreak(text: string, start: number, end
     return end;
   }
   const adjusted = end - 1;
-  return adjusted > start ? adjusted : end;
+  return adjusted > start ? adjusted : end + 1;
 }
 
 export function chunkTextByBreakResolver(