This CL attempts to hide panels from the user view until
data upload event to help users read instructions more easily.

Screenshots: https://imgur.com/a/qFgIKI8

Bug: v8:10665
Change-Id: Ida666aa850b80cff3f428e1789cc92592ec79a6c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2278474Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Cr-Commit-Position: refs/heads/master@{#68738}