PSM: Fix the pre-condition of calling SetUp of base test class

Previously, Hash dance was running sequentially after PSM. Therefore,
there was a need to force enabled PSM, then calling base test class
SetUp to create the client correctly.

At the moment, PSM is always enabled by default for initial enrollment
and the only source of truth. However, the base SetUp needs to be
called only after the PSM RLWE client factory has been created.
Otherwise PSM will fail.

This CL is adjusting the pre-condition comment of calling
the base SetUp testing class.

Bug: 1242309
Change-Id: Iacf176005b0be902e5eb7bc6aa0fc827c3ef8219
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3113936


Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Auto-Submit: Amr Aboelkher <amraboelkher@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/main@{#915142}