Copy IpSecConfig when IpSecTransforms are created

This change prevents IpSecTransforms from being inadvertently modified
by changes to the IpSecConfig. Specifically, once the transform is
created, it takes a copy of the config, rather than a reference.

Bug: 69385347
Test: New tests added, and all test passing
Change-Id: I89b8660c175ca20aa70352dcda893434ff7fd42b