CSS: Upgrade to Font-Awesome 6.7.1

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/src/third-party/Font-Awesome b/src/third-party/Font-Awesome
index 0698449d50f2b95517562295a59d414afc68b369..3447c58c6b3ff327b35171d866ec70c25c72f4ef 160000 (submodule)
--- a/src/third-party/Font-Awesome
+++ b/src/third-party/Font-Awesome
@@ -1 +1 @@
-Subproject commit 0698449d50f2b95517562295a59d414afc68b369
+Subproject commit 3447c58c6b3ff327b35171d866ec70c25c72f4ef