refactor: let the periodic work run more frequently and never fail from excessive retries preventing from re-running.

remove resume pending jobs from ApplicationContext onCreate and handle in home activity's onCreate instead.

prevent some illegal argument exceptions from Random.kt by returning null if empty

libsignal/src/main/java/org/session/libsignal/service/loki/Random.kt

@@ -6,6 +6,7 @@ import java.security.SecureRandom
  * Uses `SecureRandom` to pick an element from this collection.
  */
 fun <T> Collection<T>.getRandomElementOrNull(): T? {
+    if (isEmpty()) return null
     val index = SecureRandom().nextInt(size) // SecureRandom() should be cryptographically secure
     return elementAtOrNull(index)
 }