Fix a potential bug in the stop method.

Author: jaynewstrom-stripe

android/src/main/java/com/reactnativestripesdk/utils/KeepJsAwakeTask.kt

@@ -33,7 +33,14 @@ internal class KeepJsAwakeTask(
   fun stop() {
     val taskId = taskId ?: return
     val headlessJsTaskContext = HeadlessJsTaskContext.getInstance(context)
-    headlessJsTaskContext.finishTask(taskId)
-    this.taskId = null
+
+    try {
+        headlessJsTaskContext.finishTask(taskId)
+    } catch (e: AssertionError) {
+        // Ignore if task already finished
+        // Log.w("KeepJsAwakeTask", "Tried to stop a non-existent task (id=$taskId)")
+    } finally {
+        this.taskId = null
+    }
   }
 }