Reduce `context.Background()`

[AkihiroSuda]

https://github.com/search?q=repo%3Alima-vm%2Flima%20context.Background&type=code

Similar to:

• Remove context.TODO() #3874

Some occurrences of context.Background() are legit and should not be removed

lima/pkg/hostagent/hostagent.go

Line 592 in f3afdb6

// using ctx.Background() because ctx has already been cancelled

[ashwat287]

@AkihiroSuda Can you please assign me the issue?