feat(ffi): expose the inviter directly on the room to avoid having to fetch the room preview

The room preview doesn't actually contain the inviter but instead retrieves it from the room invite details.

Author: stefanceriu

bindings/matrix-sdk-ffi/src/room.rs

@@ -134,6 +134,16 @@ impl Room {
         self.inner.alt_aliases().iter().map(|a| a.to_string()).collect()
     }
 
+    /// Get the user who created the invite, if any.
+    pub async fn inviter(&self) -> Result<Option<RoomMember>, ClientError> {
+        let invite_details = self.inner.invite_details().await?;
+
+        match invite_details.inviter {
+            Some(inviter) => Ok(Some(inviter.try_into()?)),
+            None => Ok(None),
+        }
+    }
+
     pub fn membership(&self) -> Membership {
         self.inner.state().into()
     }