fwupd: Use clearer key names for flag values in message parsing

When parsing a message into a dict, uint64_t flag values are converted
to boolean flags. This is necessary because base::Value has no lossless
uint64_t type.

Previously, the key name for the boolean value was the same as the key
name for the whole flag. To make the code clearer, change the key names
for the boolean values to reflect the specific flag being stored.

BUG=none
TEST=chromeos_unittests --gtest_filter=FwupdClientTest.*

Change-Id: Ie44b2ece79d0fc9e2e76fdb5b0d4db533e7a670d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5581932


Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Nicholas Bishop <nicholasbishop@google.com>
Reviewed-by: Jimmy Gong <jimmyxgong@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1313664}