Fix image not rendering after clearing cache.

libraries/matrixui/src/main/kotlin/io/element/android/libraries/matrix/ui/media/ImageLoaderHolder.kt

@@ -32,6 +32,7 @@ import javax.inject.Provider
 
 interface ImageLoaderHolder {
     fun get(client: MatrixClient): ImageLoader
+    fun remove(sessionId: SessionId)
 }
 
 @ContributesBinding(AppScope::class)
@@ -52,7 +53,7 @@ class DefaultImageLoaderHolder @Inject constructor(
             override suspend fun onSessionCreated(userId: String) = Unit
 
             override suspend fun onSessionDeleted(userId: String) {
-                map.remove(SessionId(userId))
+                remove(SessionId(userId))
             }
         })
     }
@@ -68,4 +69,10 @@ class DefaultImageLoaderHolder @Inject constructor(
             }
         }
     }
+
+    override fun remove(sessionId: SessionId) {
+        synchronized(map) {
+            map.remove(sessionId)
+        }
+    }
 }