fixup! base: add a cache to the computed display name

crates/matrix-sdk-base/src/rooms/normal.rs

@@ -12,12 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#[cfg(all(feature = "e2e-encryption", feature = "experimental-sliding-sync"))]
-use std::sync::RwLock as SyncRwLock;
 use std::{
     collections::{BTreeMap, HashSet},
     mem,
-    sync::{atomic::AtomicBool, Arc},
+    sync::{atomic::AtomicBool, Arc, RwLock as SyncRwLock},
 };
 
 use bitflags::bitflags;