LibWeb: Move cells positioning in separate function in TFC

Author: https://github.com/kalenikaliaksandr
Commit: 0e1da540b6
Pull-request: https://github.com/SerenityOS/serenity/pull/16899
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibWeb/Layout/TableFormattingContext.h

@@ -27,6 +27,7 @@ private:
     void determine_intrisic_size_of_table_container(AvailableSpace const& available_space);
     void calculate_row_heights();
     void position_row_boxes();
+    void position_cell_boxes();
 
     CSSPixels m_automatic_content_height { 0 };