Improve error handling

[dnicolson]

♻️ Current situation

Some unhandled errors result in unreadable exceptions in Homebridge when using homebridge-switchbot.

💡 Proposed solution

Handle errors more gracefully, it's likely that they could be prevented by changes in the async logic in this package.

3d4511a fixes the following error in Homebridge:

Bot: Light failed BLEpushChanges with BLE Connection & botMode: switch, Error Message: "Cannot read properties of undefined (reading 'turnOn')"
TypeError: Cannot read properties of undefined (reading 'turnOn')
    at fn (/usr/lib/node_modules/@switchbot/homebridge-switchbot/src/device/bot.ts:666:18)
    at Bot.retry (/usr/lib/node_modules/@switchbot/homebridge-switchbot/dist/device/bot.js:1115:16)
    at /usr/lib/node_modules/@switchbot/homebridge-switchbot/src/device/bot.ts:661:26
    at runNextTicks (node:internal/process/task_queues:60:5)
    at processTimers (node:internal/timers:504:9)

642e429 fixes the following error in Homebridge:

Curtain: Curtain failed BLEpushChanges with BLE Connection, Error Message: "Cannot read properties of null (reading 'write')"
TypeError: Cannot read properties of null (reading 'write')
TypeError: Cannot read properties of null (reading 'write')
    at /usr/lib/node_modules/@switchbot/homebridge-switchbot/node_modules/node-switchbot/lib/switchbot-device.js:449:42
    at runNextTicks (node:internal/process/task_queues:60:5)
    at listOnTimeout (node:internal/timers:533:9)
    at processTimers (node:internal/timers:507:7)

The latter error is easy to trigger from Homebridge by repeatedly switching a Bot off and on. This also causes all of Homebridge devices to become unresponsive for a short period of time.

[donavanbecker]

Thanks @dnicolson!