Avoids crash in ADM for Android

Tbr: henrik.lundin
Bug: webrtc:11270
Change-Id: I1b3ad0afe3f5072ea4529e89729b087a4bd29fec
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/165396
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Henrik Andreassson <henrika@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30197}

sdk/android/src/java/org/webrtc/audio/WebRtcAudioRecord.java

@@ -426,6 +426,9 @@ class WebRtcAudioRecord {
       Logging.w(TAG, "AudioManager#getActiveRecordingConfigurations() requires N or higher");
       return 0;
     }
+    if (audioRecord == null) {
+      return 0;
+    }
     // Get a list of the currently active audio recording configurations of the device (can be more
     // than one). An empty list indicates there is no recording active when queried.
     List<AudioRecordingConfiguration> configs = audioManager.getActiveRecordingConfigurations();