Fix implementation of installOnNode for phones

[luizgrp]

WHAT

Fix implementation of installOnNode for phones.

WHY

• From RemoteActivityHelper#getAvailabilityStatus:

On phone devices, it will always return STATUS_UNKNOWN

• Missed adding comment to the watch implementation, requested in Improve installOnNode to return AppHelperResultCode #1992 (comment)

HOW

Checklist 📋

• [N/A] Add explicit visibility modifier and explicit return types for public declarations
• Run spotless check
• Run tests
• [N/A] Update metalava's signature text files

[yschimke]

So not broken, just pointless to check?

[luizgrp]

So not broken, just pointless to check?

Yes, based on my understanding of the docs. Just when called by phones, for watches it is advised to check.