[MEP] Handle downloadSubscription with switchAfterDownload is set to true

Most of cases, download opperation is port agnostic we don't need to specify the portIndex. However if this is triggered from carier apps and apps specify download followed with esim activation, then platform need to resolve a portIndex(maybe through UX) and need to pass this portIndex to LPA app. Also If cannot resolve port Index, request user confirmation with new UX dialog to support MEP feature.

Bug: 220060771
Test: Manual test with Fi, atest FrameworksTelephonyTests
Change-Id: Id27bdc3d802bb5f2fb3459ec62be75365a2222b8