Avoid setting avatar_url to ""

Fixes an edge-case bug where calling `set_avatar_url("")` when the user
doesn't have an avatar(`get_avatar_url()` returns `None`) caused a
redundant PUT request to be made to nullify the already-empty avatar_url
field in the user profile. This also fixes the errant `$user made no
change` state events appearing in every room they are in when
`set_avatar_url("")` is called.

Signed-off-by: Joe Groocock <me@frebib.net>

mautrix/client/api/user_data.py

@@ -71,7 +71,7 @@ async def search_users(self, search_query: str, limit: int | None = 10) -> UserS
     # region 10.2 Profiles
     # API reference: https://matrix.org/docs/spec/client_server/r0.4.0.html#profiles
 
-    async def set_displayname(self, displayname: str, check_current: bool = True) -> None:
+    async def set_displayname(self, displayname: str | None, check_current: bool = True) -> None:
         """
         Set the display name of the current user.
 
@@ -81,7 +81,9 @@ async def set_displayname(self, displayname: str, check_current: bool = True) ->
             displayname: The new display name for the user.
             check_current: Whether or not to check if the displayname is already set.
         """
-        if check_current and await self.get_displayname(self.mxid) == displayname:
+        if check_current and str_or_none(await self.get_displayname(self.mxid)) == str_or_none(
+            displayname
+        ):
             return
         await self.api.request(
             Method.PUT,
@@ -112,7 +114,9 @@ async def get_displayname(self, user_id: UserID) -> str | None:
         except KeyError:
             return None
 
-    async def set_avatar_url(self, avatar_url: ContentURI, check_current: bool = True) -> None:
+    async def set_avatar_url(
+        self, avatar_url: ContentURI | None, check_current: bool = True
+    ) -> None:
         """
         Set the avatar of the current user.
 
@@ -122,7 +126,9 @@ async def set_avatar_url(self, avatar_url: ContentURI, check_current: bool = Tru
             avatar_url: The ``mxc://`` URI to the new avatar.
             check_current: Whether or not to check if the avatar is already set.
         """
-        if check_current and await self.get_avatar_url(self.mxid) == avatar_url:
+        if check_current and str_or_none(await self.get_avatar_url(self.mxid)) == str_or_none(
+            avatar_url
+        ):
             return
         await self.api.request(
             Method.PUT,
@@ -185,3 +191,10 @@ async def beeper_update_profile(self, custom_fields: dict[str, Any]) -> None:
         await self.api.request(Method.PATCH, Path.v3.profile[self.mxid], custom_fields)
 
     # endregion
+
+
+def str_or_none(v: str | None) -> str | None:
+    """
+    str_or_none empty string values to None
+    """
+    return None if v == "" else v