Update for AutofillRetrieveOverallPredictionsFromCacheV2 experiment

This limits the test config to a version of
AutofillRetrieveOverallPredictionsFromCacheV2 without cleanup because
the cleanup produces some incorrect UMA metrics. I need to fix the
code first before proceeding with the cleanup.

Bug: 1373362
Change-Id: I10ad4d71db730051799fd117f97b1efc20d3249d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4181116
Commit-Queue: Christoph Schwering <schwering@google.com>
Auto-Submit: Dominic Battré <battre@chromium.org>
Reviewed-by: Christoph Schwering <schwering@google.com>
Cr-Commit-Position: refs/heads/main@{#1095110}