Update changelog, and use default user icon instead of user avatar, so to not leak the user in anon commands

Author: Taaku18

CHANGELOG.md

@@ -15,8 +15,14 @@ however, insignificant breaking changes do not guarantee a major version bump, s
 
 ### Fixed
 
+- Not having a guild icon no longer raises an exception. ([PR #3235](https://github.com/kyb3r/modmail/pull/3235))
+  - When no icon is set, use the default user icon.
 - Resolved an issue where `?logs` doesn't work when the thread has no title. ([PR #3201](https://github.com/kyb3r/modmail/pull/3201))
 
+### Changed
+
+- Plain messages no longer forces `()` around the respondent text. ([PR #3234](https://github.com/kyb3r/modmail/pull/3234))
+
 # v4.0.1
 
 This is a hotfix release.

bot.py

@@ -94,7 +94,7 @@ def get_guild_icon(self, guild: typing.Optional[discord.Guild]) -> str:
         if guild is None:
             guild = self.guild
         if guild.icon is None:
-            return self.user.display_avatar.url
+            return "https://cdn.discordapp.com/embed/avatars/0.png"
         return guild.icon.url
 
     def _resolve_snippet(self, name: str) -> typing.Optional[str]: