Add awaitEspPacket that requires sequence number match

This is a preparation patch for improving
testRequestIpSecTransformStateForTx

This patch:
- Adds another awaitEspPacket method that requires sequence number
  match
- Defines ICMP header length in the PacketUtils

Bug: 358324865
Test: atest IpSecManagerTunnelTest
Flag: Exempt test code only
(cherry picked from https://android-review.googlesource.com/q/commit:721772d97eb9297bd098aa2d9243872e74a0fa97)
Merged-In: I5365c4daf983cc98f8f869a30cee1799138fa2b3
Change-Id: I5365c4daf983cc98f8f869a30cee1799138fa2b3
2 files changed