Make confirmation message scroll in PiaV2

In case the dialog message in install confirmation dialog is long, it
may get clipped if the device is in landscape mode, screen is small or
font is large. Ensure that the dialog message is scrollable

Bug: 316211161
Test: Manual. Follow repro steps in the bug
Change-Id: Icf564c7007f26192c9e353114daaf03fe35e0b5e