Revert "Fix text warp in color blocks with CJK"

This reverts commit cd778e00dc.

That commit introduced regressions for non-CJK languages are discussed
in #8952. Fixes #9078.

scene/gui/rich_text_label.cpp

@@ -264,7 +264,7 @@ void RichTextLabel::_process_line(ItemFrame *p_frame, const Vector2 &p_ofs, int
 							cw = tab_size * font->get_char_size(' ').width;
 						}
 
-						if (end > 0 && w + cw + wofs > p_width) {
+						if (end > 0 && w + cw + begin > p_width) {
 							break; //don't allow lines longer than assigned width
 						}