Kernel: Use TRY() in sys$alarm()

Kernel/Syscalls/alarm.cpp

@@ -30,9 +30,7 @@ KResultOr<FlatPtr> Process::sys$alarm(unsigned seconds)
         auto deadline = TimeManagement::the().current_time(CLOCK_REALTIME_COARSE);
         deadline = deadline + Time::from_seconds(seconds);
         if (!m_alarm_timer) {
-            m_alarm_timer = adopt_ref_if_nonnull(new (nothrow) Timer());
-            if (!m_alarm_timer)
-                return ENOMEM;
+            m_alarm_timer = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Timer));
         }
         auto timer_was_added = TimerQueue::the().add_timer_without_id(*m_alarm_timer, CLOCK_REALTIME_COARSE, deadline, [this]() {
             [[maybe_unused]] auto rc = send_signal(SIGALRM, nullptr);