PWMGR_SAVING_ENABLED and PWMGR_NUM_SAVED_PASSWORDS are removed,
with Glean alternatives implemented. The new metrics always have the correct
value and will report them in every "metrics" ping.
PWMGR_BLOCKLIST_NUM_SITES, PWMGR_NUM_HTTPAUTH_PASSWORDS,
PWMGR_USERNAME_PRESENT, PWMGR_LOGIN_LAST_USED_DAYS, and
PWMGR_NUM_PASSWORDS_PER_HOSTNAME are merely removed.
Differential Revision: https://phabricator.services.mozilla.com/D239757
92ab7327c3