doc: replace the broken link in the ColorTool notices file (#19523)

tango-project seems to have rotted. Replace it with a Web Archive link.

Author: stynixkis

src/tools/ColorTool/ThirdPartyNotices.md

@@ -54,4 +54,4 @@ Tango Dark and Light Schemes
 ----------------------------
 Released to the public domain by the Tango Desktop Project in 2009.
 
-http://tango-project.org
+https://web.archive.org/web/20160105113523/http://tango.freedesktop.org/