Don't let refresh requests pile up while not awake

[tstabrawa]

This change fixes a bug whereby identical refresh requests may pile up in a non-awake device's send queue over time. For example, I had an automation running at 15-minute intervals that would perform a refresh-all command. Several days later, when I performed an "awake" command against a mini-remote device (2342-232), Insteon-MQTT tried to send several hundred refresh commands to the mini-remote.

This change avoids queuing more than one refresh command by replacing identical queued refresh commands with newly-received refresh commands (under the assumption that it might be more convenient to the user if the new command is still waiting for a response at the time the device is woken up).

Confirmed no new flake8 errors, pylint errors, or code coverage gaps. All tests passing. Also, confirmed new test (test_queued_refresh_replace) fails prior to applying fix:

================================================================================ FAILURES ================================================================================
______________________________________________________________ Test_Base_Config.test_queued_refresh_replace ______________________________________________________________

self = <test_BatterySensorDev.Test_Base_Config object at 0x7f209f3739a0>, test_device = <insteon_mqtt.device.BatterySensor.BatterySensor object at 0x7f209ed35000>

    def test_queued_refresh_replace(self, test_device):
        # Queue multiple refresh commands
        msg1 = Msg.OutStandard.direct(test_device.addr, 0x19, 0x00)
        msg2 = Msg.OutStandard.direct(test_device.addr, 0x19, 0x00)
        msg3 = Msg.OutStandard.direct(test_device.addr, 0x19, 0x00)
        msg_handler1 = IM.handler.StandardCmd(msg1, None, None)
        msg_handler2 = IM.handler.StandardCmd(msg2, None, None)
        msg_handler3 = IM.handler.StandardCmd(msg3, None, None)
        test_device.send(msg1, msg_handler1)
        test_device.send(msg2, msg_handler2)
        test_device.send(msg3, msg_handler3)
        # Confirm that only the last command is queued
>       assert len(test_device._send_queue) == 1
E       assert 3 == 1
E        +  where 3 = len([[<insteon_mqtt.message.OutStandard.OutStandard object at 0x7f209ed34700>, <insteon_mqtt.handler.StandardCmd.StandardC...ndard object at 0x7f209ed37fa0>, <insteon_mqtt.handler.StandardCmd.StandardCmd object at 0x7f209ed36f20>, False, None]])
E        +    where [[<insteon_mqtt.message.OutStandard.OutStandard object at 0x7f209ed34700>, <insteon_mqtt.handler.StandardCmd.StandardC...ndard object at 0x7f209ed37fa0>, <insteon_mqtt.handler.StandardCmd.StandardCmd object at 0x7f209ed36f20>, False, None]] = <insteon_mqtt.device.BatterySensor.BatterySensor object at 0x7f209ed35000>._send_queue

tests/device/test_BatterySensorDev.py:149: AssertionError
======================================================================== short test summary info =========================================================================
FAILED tests/device/test_BatterySensorDev.py::Test_Base_Config::test_queued_refresh_replace - assert 3 == 1
===================================================================== 1 failed, 706 passed in 10.71s =====================================================================

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.
• Code documentation was added where necessary - N/A

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated - N/A