Revert "port Product usage analytics' 1 variable to FormSpec"

Revert submission 151298

Reason for revert: causes broken test_otel_configuration_quick_setup in test-system-gui-ultimate

Reverted changes: /q/submissionid:151298

Change-Id: I275bcd0d6c965801a225c6853cf3e86e4c4e1b2b