change (media preview config) : use the new apis

libraries/preferences/test/src/main/kotlin/io/element/android/libraries/preferences/test/InMemoryAppPreferencesStore.kt

@@ -55,18 +55,10 @@ class InMemoryAppPreferencesStore(
         return theme
     }
 
-    override suspend fun setHideInviteAvatars(value: Boolean) {
-        hideInviteAvatars.value = value
-    }
-
     override fun getHideInviteAvatarsFlow(): Flow<Boolean> {
         return hideInviteAvatars
     }
 
-    override suspend fun setTimelineMediaPreviewValue(value: MediaPreviewValue) {
-        timelineMediaPreviewValue.value = value
-    }
-
     override fun getTimelineMediaPreviewValueFlow(): Flow<MediaPreviewValue> {
         return timelineMediaPreviewValue
     }