Fix issues on EuiccCard constructor.

1) Lazy-initialize mEidReadyRegistrants. Otherwise, mEidReadyRegistrants, which is a member
in EuiccCard, should only be accessed after the constructor of UiccCard is finished.
2) remove a todo in UiccController since getCardId() has been added.
3) Check whether EuiccCard is null in EuiccCardController.

Bug: 38206971
Test: test on phone
Merged-In: I6a195d7b80df0490fb10304f666d41aba2dcfbf1
Change-Id: I6a195d7b80df0490fb10304f666d41aba2dcfbf1