lotus-stats tool shows negative power when network power is over ~8 EiB

[travisperson]

Checklist

• This is not a security-related bug/issue. If it is, please follow please follow the security policy.
• This is not a question or a support request. If you have any lotus related questions, please ask in the lotus forum.
• This is not a new feature request. If it is, please file a feature request instead.
• This is not an enhancement request. If it is, please file a improvement suggestion instead.
• I have searched on the issue tracker and the lotus forum, and there is no existing related issue or discussion.
• I am running the Latest release, or the most recent RC(release canadiate) for the upcoming release or the dev branch(master), or have an issue updating to any of these.
• I did not make any code changes to lotus.

Lotus component

Other

Lotus Version

not part of lotus

Describe the Bug

When network power is over ~8EiB the lotus status tool and dashboard report an negative power.

Logging Information

no logs

Repo Steps

No response

[travisperson]

https://github.com/filecoin-project/lotus/blame/v1.11.1-rc1/tools/stats/metrics.go#L284-L292

This is at least one source of the issue, we should be grabbing this as a Uint64. I do not know at the moment if there will be further issues pushing a value this large into influx, or graphing it in grafana though.