Improvement to user switching intents

[timelord1102]

Description

Currently adb intents to switch users require an itemId. This makes it impossible to switch users on the home page via intents, and therefore makes some automations impossible.

I would love to see itemId become optional with behaviour either defaulting to home, or even just switching users while staying on the same content. Either one would allow for proper user switching automations.

[Kooldude93]

Chiming in to say that this would be very useful for users running software like Home Assistant which lets you create custom remotes for tablets and smart phones.

[timelord1102]

Haha my exact usecase

[damontecres]

Sure this makes sense and shouldn't be too complicated to implement.

[damontecres]

Adding in #1962