Update IpSecManager to use InetAddress and prefixLen

LinkAddress constructors are currently @hide; this change updates
IpSecManager to use InetAddress and prefixLen, and then construct a
LinkAddress internally. LinkAddress is used over the binder interface to
IpSecService to ensure validity.

Bug: 77528639
Test: CTS, Java unit tests ran on walleye
Merged-In: I19e124adef6d9f4992d8293db3190bcf74c95848
Change-Id: I19e124adef6d9f4992d8293db3190bcf74c95848
(cherry picked from commit 3f2c54b7)