Revert "Fix ftxui build in windows (#17333, #19626)" (#19716)

Author: eivanov89

contrib/libs/ftxui/ya.make

@@ -22,13 +22,6 @@ NO_COMPILER_WARNINGS()
 
 NO_UTIL()
 
-IF (OS_WINDOWS)
-    CFLAGS(
-        -DUNICODE
-        -D_UNICODE
-    )
-ENDIF()
-
 SRCS(
     src/ftxui/component/animation.cpp
     src/ftxui/component/button.cpp