base: Add room member ID to AmbiguityChange

Makes AmbiguityChange easier to use, especially outside of SyncResponse,
where we might not have the m.room.member event.

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

crates/matrix-sdk-base/src/deserialized_responses.rs

@@ -34,9 +34,12 @@ use serde::Serialize;
 
 /// A change in ambiguity of room members that an `m.room.member` event
 /// triggers.
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug)]
 #[non_exhaustive]
 pub struct AmbiguityChange {
+    /// The user ID of the member that is contained in the state key of the
+    /// `m.room.member` event.
+    pub member_id: OwnedUserId,
     /// Is the member that is contained in the state key of the `m.room.member`
     /// event itself ambiguous because of the event.
     pub member_ambiguous: bool,

crates/matrix-sdk-base/src/store/ambiguity_map.rs

@@ -118,6 +118,7 @@ impl AmbiguityCache {
         self.update(room_id, old_map, new_map);
 
         let change = AmbiguityChange {
+            member_id: member_event.state_key().clone(),
             disambiguated_member,
             ambiguated_member,
             member_ambiguous: ambiguous,