fix dingtalk icon url (#15417)

Author: tomaswarynyca

templates/org/settings/hook_new.tmpl

@@ -18,7 +18,7 @@
 						{{else if eq .HookType "discord"}}
 							<img width="26" height="26" src="{{StaticUrlPrefix}}/img/discord.png">
 						{{else if eq .HookType "dingtalk"}}
-							<img width="26" height="26" src="{{StaticUrlPrefix}}/img/dingtalk.png">
+							<img width="26" height="26" src="{{StaticUrlPrefix}}/img/dingtalk.ico">
 						{{else if eq .HookType "telegram"}}
 							<img width="26" height="26" src="{{StaticUrlPrefix}}/img/telegram.png">
 						{{else if eq .HookType "msteams"}}