Remove the WRITE_EXTERNAL_STORAGE permission

[jakub-uber]

The library contains the runtime permission WRITE_EXTERNAL_STORAGE. However, the documentation doesn't mention any use case for it and it seams to be unused. It should be removed from the library manifest. Alternatively, the purpose of this permission should be explained in the documentation.

[Riadzebra]

This permission is needed. we will work on updating the documentation .

[Riadzebra]

The permision is required for SMS and firmware updates
https://techdocs.zebra.com/dcs/scanners/sdk-android/dev-guide/#:~:text=false%3B%0A%7D-,Firmware%20Update,-Firmware%20can%20be
https://techdocs.zebra.com/dcs/scanners/sdk-android/dev-guide/#:~:text=First%2C%20permissions%20must%20be%20included%20in%20the%20Manifest%20file%20for%20the%20device%20to%20access%20SMS%20Package%20files%20in%20the%20storage.
https://techdocs.zebra.com/dcs/scanners/sdk-android/dev-guide/#:~:text=//Read%20and%20Write%20permission%20is%20required%20to%20extract%20the%20SMS%20package%20file.