[Room List] Show offline indicator when the device is offline (#239)

* Implement the network status indicator.

* Add `networkmonitor` feature.

features/networkmonitor/test/build.gradle.kts

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+/*
+ * Copyright (c) 2022 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.
+ */
+
+// TODO: Remove once https://youtrack.jetbrains.com/issue/KTIJ-19369 is fixed
+@Suppress("DSL_SCOPE_VIOLATION")
+plugins {
+    id("io.element.android-library")
+}
+
+android {
+    namespace = "io.element.android.features.networkmonitor.test"
+}
+
+dependencies {
+    api(projects.features.networkmonitor.api)
+    api(libs.coroutines.core)
+}

features/networkmonitor/test/src/main/kotlin/io/element/android/features/networkmonitor/test/FakeNetworkMonitor.kt

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+/*
+ * 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.features.networkmonitor.test
+
+import io.element.android.features.networkmonitor.api.NetworkMonitor
+import io.element.android.features.networkmonitor.api.NetworkStatus
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+
+class FakeNetworkMonitor(initialStatus: NetworkStatus = NetworkStatus.Online) : NetworkMonitor {
+    override val currentConnectivityStatus: NetworkStatus
+        get() = _connectivityStatus.value
+
+    private val _connectivityStatus: MutableStateFlow<NetworkStatus> = MutableStateFlow(initialStatus)
+    override val connectivity: Flow<NetworkStatus> = _connectivityStatus
+}