[Code health] Stop exposing `Activity` to managers

[gino-m]

[anandwana001]

Any example @gino-m

[shobhitagarwal1612]

ActivityStreams.kt?

[gino-m]

I think we should evaluate all uses of withActivity and come up with a simpler approach. Passing the Activity through a Flow is likely to lead to memory leaks and race conditions.