DeviceEventFactory: Modified event factory to provide correct value for buttons property (part deux)

[PolygonalSun]

This PR is a fix to #13927. It addresses some of the logic changes but also re-adds support for buttons in Native pointer events.

[bjsplat]

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[bjsplat]

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[RaananW]

LGTM! makes sense (especially setting the buttons value correctly)

[CedricGuillemet]

Tested OK with gizmo PG