API reports 100% full when an unknown value is reported

[alex-taffe]

On this line, we're making an assumption of 100% full. I haven't actually seen the API responses in depth, but it seems like None should be the default. If something like 5% comes back, we're mapping to 100%. Though I'm also not sure why 100, 40, 10 are the only defaults when the app shows 100, ⅔, ⅓, or empty (I'm guessing Rheem is dumb)