Disable location sharing when no MapTiler config is available

LocationService now exposes the MapTiler config to use: the one provided by the
homeserver takes precedence over the build time one, and null means that no map
provider is configured. It is now session scoped, and isServiceAvailable()
returns a StateFlow derived from this config.

When no config is available:
- the location sharing option is hidden from the composer, and location events
  cannot be opened in the location viewer;
- the "Location sharing" entry is hidden from the settings;
- location events in the timeline render a placeholder, without performing any
  request to MapTiler.

The show and share location screens now get the config from LocationService
rather than fetching the homeserver config by themselves.

Closes element-hq/element-android-enterprise#69

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

appnav/src/main/kotlin/io/element/android/appnav/LoggedInFlowNode.kt

@@ -14,7 +14,6 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.lifecycle.lifecycleScope
@@ -52,13 +51,13 @@ import io.element.android.features.callnative.api.NativeCallHost
 import io.element.android.features.createroom.api.CreateRoomEntryPoint
 import io.element.android.features.enterprise.api.EnterpriseService
 import io.element.android.features.enterprise.api.SessionEnterpriseService
-import io.element.android.features.enterprise.api.remoteconfig.CustomMapTilerConfigProvider
 import io.element.android.features.ftue.api.FtueEntryPoint
 import io.element.android.features.ftue.api.state.FtueService
 import io.element.android.features.ftue.api.state.FtueState
 import io.element.android.features.home.api.HomeEntryPoint
 import io.element.android.features.linknewdevice.api.LinkNewDeviceEntryPoint
 import io.element.android.features.location.api.LocalMapTilerConfig
+import io.element.android.features.location.api.LocationService
 import io.element.android.features.location.api.live.ActiveLiveLocationShareManager
 import io.element.android.features.networkmonitor.api.NetworkMonitor
 import io.element.android.features.networkmonitor.api.NetworkStatus
@@ -153,7 +152,7 @@ class LoggedInFlowNode(
     private val analyticsRoomListStateWatcher: AnalyticsRoomListStateWatcher,
     private val createRoomEntryPoint: CreateRoomEntryPoint,
     private val activeLiveLocationShareManager: ActiveLiveLocationShareManager,
-    private val customMapTilerConfigProvider: CustomMapTilerConfigProvider,
+    private val locationService: LocationService,
     private val loggedInEventProcessorFactory: LoggedInEventProcessor.Factory,
 ) : BaseFlowNode<LoggedInFlowNode.NavTarget>(
     backstack = BackStack(
@@ -636,10 +635,7 @@ class LoggedInFlowNode(
             enterpriseService.semanticColorsFlow(sessionId = matrixClient.sessionId)
         }.collectAsState(SemanticColorsLightDark.default)
 
-        val currentMapTilerConfig = LocalMapTilerConfig.current
-        val updatedMapTilerConfig by produceState(currentMapTilerConfig) {
-            value = customMapTilerConfigProvider.get().getOrNull() ?: currentMapTilerConfig
-        }
+        val mapTilerConfig by locationService.mapTilerConfig.collectAsState()
 
         ElementThemeApp(
             appPreferencesStore = appPreferencesStore,
@@ -648,7 +644,7 @@ class LoggedInFlowNode(
             compoundDark = colors.dark,
             buildMeta = buildMeta,
         ) {
-            CompositionLocalProvider(LocalMapTilerConfig provides updatedMapTilerConfig) {
+            CompositionLocalProvider(LocalMapTilerConfig provides mapTilerConfig) {
                 val isOnline by syncService.isOnline.collectAsState()
                 // Outside the connectivity indicator so the two strips stack rather than fight: an
                 // offline banner during a call belongs under the call bar, not over it.