Switch to using an intent for eSIM erasing

We initially landed support for erasing an eSIM subscription in
ag/7208624 for b/124254555 using our own confirmation/progress UI, and
calling the EuiccManager.deleteSubscription method to do the
deletion. It turns out this is a low-level API which doesn't handle some
important cases such as subscription grouping or the eSIM slot not being
active.

This CL changes Settings to just launch an intent to begin an eSIM
Manager flow to delete a subscription that provides its own
confirmation/progress UI, and should properly handle subscription
grouping and making the eSIM slot active as needed.

Bug: 132114333
Test: make RunSettingsRoboTests
Change-Id: Ie59fea37fa73c5e6573e1181e271ffb5d453bd08