Sync flag icons with upstream

* Includes all 268 flags.
* Upstream commit `a7b7c3c55560cb39d96e70324876e1bb5b1c625b` - (Release v6.11.0)
* Flags source from (zip): https://github.com/lipis/flag-icons/releases/tag/v6.11.0

PR #19518.

src/icons/flags/im.svg

@@ -1,10 +1,10 @@
 <svg xmlns="http://www.w3.org/2000/svg" id="flag-icons-im" viewBox="0 0 640 480">
   <defs>
-    <clipPath id="a">
+    <clipPath id="im-a">
       <path fill-opacity=".7" d="M-77.6 0H605v512H-77.6z"/>
     </clipPath>
   </defs>
-  <g clip-path="url(#a)" transform="translate(72.8) scale(.94)">
+  <g clip-path="url(#im-a)" transform="translate(72.8) scale(.94)">
     <path fill="#ba0000" fill-rule="evenodd" d="M629.4 512H-102V0h731.4z"/>
     <path fill="#ffef00" fill-rule="evenodd" stroke="#000" stroke-width="2.2" d="M281 376c.2-.6.6-6.8.4-6.8s-9.4-10.9-9.2-10.9c.2 0 11.8 2.6 11.8 2.2 0-.4 4.7-11.5 4.7-11.7l5.6 13.5 11.5 5-8 6.7 1.7 13c0 .3-8-7.6-8-7.6l-8.9 1s-1.2-4-1.6-4.4z"/>
     <path fill="#fff" fill-rule="evenodd" stroke="#000" stroke-width="2.6" d="M218.7 206.9c-7.7 4-37 37.5-41 42.7a77.3 77.3 0 0 1-16.8 23.4c-7.3 5.5-11.3 13-10.3 20 0 9 4.9 15 8.8 21.1 2.3 2.9 5.5 4.7 8.8 5 6.9.8 7.5 3 11 4.2 13.4 18.4 33.6 32 48 42.7a68.4 68.4 0 0 1 18 12.4c4.2 8.2 3.4 16 2.8 20L237.3 439c-1.9 11 7.8 8.6 8.3 6.4 4.3-5.7 10.8-1.7 20-34.3l12.8-17.1s4.9-2 4.9-2.5c7.5-9 1.8-14-2.5-15.7l-9.2-3.4s-10.8-10.8-11.3-10.8c-5.1-14.9-30.3-46.6-36.1-51-4-4.3-6-6-9.8-8.4-5.9-2.8-7.8-3.8-11.4-5.2-3-1.2-.9-4.5 1-6 20-10.9 35.7-22.9 54.8-35.1l3-2-6.9-39.2-31.8-11.2c-1.7 1.1-3 2.3-4.4 3.4z"/>