call: prevent toggle speakerphone to crash

First shot to prevent it to crash.
However conf.call is always null in conference mode so the functionality doesn't work.
GitLab: #1405

Change-Id: I73e3593e4a860925e96d0b20c73ba2aeacae7a5c

jami-android/app/src/main/java/cx/ring/services/HardwareServiceImpl.kt

@@ -324,29 +324,37 @@ class HardwareServiceImpl(
     @Synchronized
     override fun toggleSpeakerphone(conf: Conference, checked: Boolean) {
         Log.w(TAG, "toggleSpeakerphone $conf $checked")
+
+        conf.call?.let { call ->
             val hasVideo = conf.hasActiveVideo()
-        disposables.add(conf.call!!.systemConnection
+            disposables.add(
+                call.systemConnection
                     .map {
                         // Map before subscribe to fallback to the error path if no Telecom API
                         (it as CallServiceImpl.AndroidCall).connection!!
                     }
                     .subscribe({
                         // Using the Telecom API
-                it.setWantedAudioState(if (checked) CallConnection.ROUTE_LIST_SPEAKER_EXPLICIT
+                        it.setWantedAudioState(
+                            if (checked) CallConnection.ROUTE_LIST_SPEAKER_EXPLICIT
                             else if (hasVideo) CallConnection.ROUTE_LIST_SPEAKER_IMPLICIT
-                else CallConnection.ROUTE_LIST_DEFAULT)
+                            else CallConnection.ROUTE_LIST_DEFAULT
+                        )
                     }) {
                         // Fallback to the AudioManager API
                         JamiService.setAudioPlugin(JamiService.getCurrentAudioOutputPlugin())
                         mShouldSpeakerphone = checked
                         if (mHasSpeakerPhone && checked) {
                             routeToSpeaker()
-                } else if (mBluetoothWrapper != null && mBluetoothWrapper!!.canBluetooth()) {
+                        } else
+                            if (mBluetoothWrapper != null && mBluetoothWrapper!!.canBluetooth()) {
                                 routeToBTHeadset()
                             } else {
                                 resetAudio()
                             }
-            })
+                    }
+            )
+        } ?: Log.e(TAG, "This is a bug. Cannot toggle speaker phone as conference call is null.")
     }
 
     @Synchronized