fix(diagnostic): corrects isEnabled functions to isAvailable

[amuramoto]

• Location, camera, wifi, and bluetooth 'isEnabled' functions are incorrect. Corrected all to 'is Available'.

[amuramoto]

Fixes #365

[ihadeed]

Hey there,

Thanks for the PR.

The methods shouldn't be replaced. The plugin actually exports both isLocationAvailable and isLocationEnabled.

The current implementation of the plugin is just missing many of the functions listed here: https://www.npmjs.com/package/cordova.plugins.diagnostic

Related: #224

[ihadeed]

Just checked the docs again, you're right these should be Available instead of Enabled. But we will still be missing the Enabled functions for now.

Thanks again!