fixed crash on view intent on Android API <27

android/app/src/main/kotlin/deckers/thibault/aves/MainActivity.kt

@@ -320,7 +320,9 @@ open class MainActivity : FlutterFragmentActivity() {
 
                     val keyguardManager = getSystemService(Context.KEYGUARD_SERVICE) as android.app.KeyguardManager
                     val isLocked = keyguardManager.isKeyguardLocked
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
                         setShowWhenLocked(isLocked)
+                    }
                     if (isLocked) {
                         // device is locked, so access to content is limited to intent URI by default
                         fields[INTENT_DATA_KEY_SECURE_URIS] = listOf(uri.toString())