Fix logic for removable eUICCs being default

Currently the logic for whether to let a removable eUICC be the
default checks that there is no built-in eUICC. This leads to issues
when there is a built-in eUICC but it's inactive. In that case we
should still set the removable eUICC to the default, so this CL updates
the logic to check if there is a built-in *active* eUICC.

Bug: 141026212
Test: manually verified that a removable eUICC was selected as default
on Sargo with built-in eSIM inactive, also atest UiccControllerTest
Change-Id: I6e6a97af53303eca1a34ff3efd708ea02f0ff5d3
Merged-In: I6e6a97af53303eca1a34ff3efd708ea02f0ff5d3