[Alexa Plugin] syncedDevices StorageSetting not created automatically

[lippertmarkus]

Describe the bug Alexa Plugin fails to store the endpoints because the syncedDevices storage setting is not present after installation of the plugin

To Reproduce Steps to reproduce the behavior:

1. Install the Alexa Plugin
2. Enable the Skill via Alexa app
3. Observe errors like the following in the console when there are events (motion, button press, etc.):

   unhandledRejection TypeError: a is not iterable
   at h.saveEndpoints (/src/main.ts:361:33)
   at h.syncEndpoints (/src/main.ts:349:20)
   at process.this (node:internal/process/task_queues:95:5)
   at h.start (/src/main.ts:95:17)

   unhandledRejection TypeError: Cannot read properties of undefined (reading 'includes')
   at h.deviceListen (/src/main.ts:153:56)
   at h.<anonymous> (/src/main.ts:93:22)
   at processTicksAndRejections (node:internal/process/task_queues:95:5)

4. Check the Plugin storage and see that the key syncedDevices isn't available, leading to the above errors.

Expected behavior syncedDevices should be automatically created with an empty array [] as content

Screenshots If applicable, add screenshots to help explain your problem.

Server (please complete the following information):

• OS: Debian
• Installation Method: Docker

Hardware Model (please complete the following information):

• Device: Reolink Doorbell

Additional context The workaround is to create a key syncedDevices in the storage with value []

[koush]

fixed 2dd549c0