Update IpClient to support multiple IA prefix options.

Bug: 260934173
Test: atest NetworkStackIntegrationTests
Test: manually test with openwrt router that puts two IA prefix options
      in IA_PD option, one is global prefix and the other is ULA prefix,
      can see device parses both correctly and generate the IPv6 address
      based on global prefix and ignore the ULA prefix.
Change-Id: Ib55943ac88cb67b5fb76b80bc2d8ef3b4c6e63e9
3 files changed