Initial support for member suggestions (#1631)

* Initial support for member suggestion (search and UI)

* Add custom `BottomSheetScaffold` implementation to workaround several scrolling bugs

* Start searching as soon as `@` is typed, add UI following initial designs

* Extract suggestion processing code

* Extract component, add previews, fix tests

* Add tests

* Add exception from kover to the forked bottom sheet code

* Add a feature flag for mentions

- Extract composer & mention suggestions to their composable.
- Extract mentions suggestions processing to its own class.
- Add `MatrixRoom.canTriggerRoomNotification` function.
- Update strings and conditions for displaying the `@room` mention.

---------

Co-authored-by: ElementBot <benoitm+elementbot@element.io>

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/MatrixRoom.kt

@@ -130,6 +130,8 @@ interface MatrixRoom : Closeable {
 
     suspend fun canUserSendMessage(userId: UserId, type: MessageEventType): Result<Boolean>
 
+    suspend fun canUserTriggerRoomNotification(userId: UserId): Result<Boolean>
+
     suspend fun updateAvatar(mimeType: String, data: ByteArray): Result<Unit>
 
     suspend fun removeAvatar(): Result<Unit>

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/user/CurrentSessionIdHolder.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.matrix.api.user
+
+import io.element.android.libraries.di.SessionScope
+import io.element.android.libraries.di.SingleIn
+import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.core.SessionId
+import javax.inject.Inject
+
+@SingleIn(SessionScope::class)
+class CurrentSessionIdHolder @Inject constructor(matrixClient: MatrixClient) {
+    val current = matrixClient.sessionId
+
+    fun isCurrentSession(sessionId: SessionId?): Boolean = current == sessionId
+}