Improve health charts readability

[lostcontrol]

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Is your feature request related to a problem? Please describe.

Since the health charts update, I find it harder to read them. This is mainly due to too thick lines. For example, here I have almost as much IPv6 traffic as IPv4 but this is hardly visible on the chart because the blue lines are so thick they are hiding lines behind:

Also, the unit on the Y axis is a bit weird. Bytes/second makes for a lot of zeroes.

Here is another example, harder to read the before:

Also here, the unit in seconds/% (??) is weird. I think it was milliseconds before.

Describe the solution you like

Thinner lines and autoscaling units (e.g. 6 ms and not 0.006 second).

Additional context

Initial discussion: https://www.reddit.com/r/opnsense/comments/1j8pq51/comment/mh93z0v