Support for alternative role icon getters (#47)

* Support for alternative role icon getters

* Do member check and remove nested if

* redundant else

chat_exporter/construct/message.py

@@ -253,8 +253,13 @@ async def _gather_user_colour(self, author: discord.Member):
     async def _gather_user_icon(self, author: discord.Member):
         member = await self._gather_member(author)
 
-        if member and member.display_icon:
+        if not member:
+            return ""
+
+        if hasattr(member, "display_icon") and member.display_icon:
             return f"<img class='chatlog__role-icon' src='{member.display_icon}' alt='Role Icon'>"
+        elif hasattr(member, "top_role") and member.top_role and member.top_role.icon:
+            return f"<img class='chatlog__role-icon' src='{member.top_role.icon}' alt='Role Icon'>"
         return ""
 
     def set_time(self, message: Optional[discord.Message] = None):