fix(core): Use correct facebook icon provided by Meta

The legal terms require to exactly use the facebook logo as provided by Meta.

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

core/img/facebook.svg

@@ -1 +1 @@
-<svg viewBox="0 0 16 16" height="16" width="16" xmlns="http://www.w3.org/2000/svg" xml:space="preserve" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linejoin:round;stroke-miterlimit:2"><circle cx="8" cy="8" r="8" style="fill:#3a5ba2"/><path d="M0 1.831c0-138.071-111.929-250-250-250s-250 111.929-250 250c0 117.245 80.715 215.622 189.606 242.638V78.227h-51.552V1.831h51.552v-32.919c0-85.092 38.508-124.532 122.048-124.532 15.838 0 43.167 3.105 54.347 6.211v69.254c-5.901-.621-16.149-.932-28.882-.932-40.993 0-56.832 15.528-56.832 55.9V1.831h81.659l-14.028 76.396h-67.631V250C-95.927 235.049 0 129.649 0 1.831" style="fill:#fff;fill-rule:nonzero" transform="matrix(.02 0 0 .02 13 7.963)"/></svg>
+<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20"><defs><clipPath id="a" clipPathUnits="userSpaceOnUse"><path d="M-600 350h700v-700h-700Z"/></clipPath></defs><path d="M0 0c0 138.071-111.929 250-250 250S-500 138.071-500 0c0-117.245 80.715-215.622 189.606-242.638v166.242h-51.552V0h51.552v32.919c0 85.092 38.508 124.532 122.048 124.532 15.838 0 43.167-3.105 54.347-6.211V81.986c-5.901.621-16.149.932-28.882.932-40.993 0-56.832-15.528-56.832-55.9V0h81.659l-14.028-76.396h-67.631v-171.773C-95.927-233.218 0-127.818 0 0" clip-path="url(#a)" style="fill:#fff;fill-opacity:1;fill-rule:nonzero;stroke:none" transform="matrix(.032 0 0 -.032 18 10)"/></svg>