Avoid crash when checking if EuiccManager is enabled

Bug: 347624913
Test: android.carrierapi.cts.CarrierApiTest#testAddSubscriptionToExistingGroupForEsim
(cherry picked from https://android-review.googlesource.com/q/commit:f5fb983f8464fd444e51273e84dd6fca5c4872a3)
Merged-In: I918f6562949e32d3581bf0a69c9bfe02dce1cd3b
Change-Id: I918f6562949e32d3581bf0a69c9bfe02dce1cd3b
1 file changed