test(e2e): Add extra buffer in -session-max-seconds test (#4428)

This test would sometimes fail due to the diff sometimes exceeding `sessionMaxSeconds+1` by less than 1 second.

testing/internal/e2e/tests/base/target_tcp_connect_session_max_seconds_test.go

@@ -162,6 +162,6 @@ func TestCliTcpTargetConnectTargetWithSessionMaxSecondsRejectNew(t *testing.T) {
 
 	// Ensure that the session did not run for longer than the time limit
 	diff := end.Sub(start).Seconds()
-	require.Less(t, diff, float64(sessionMaxSeconds+1))
+	require.Less(t, diff, float64(sessionMaxSeconds+2))
 	require.Greater(t, diff, float64(sessionMaxSeconds-1))
 }