[Logs UI] Change tool tip labels for expected boundaries

[simianhacker]

Note: This work is blocked by elastic/elastic-charts#162

Since we can't hide data points in the tool tip we should change the labels to indicate what part of the boundaries they refer to. Instead of just listing both the boundaries as Expected we should change the respective labels to be Upper Bounds and Lower Bounds. This will be consistent to how the ML team refers to those values in their charts.

Logs UI Tool tip

ML Tool tip

[elasticmachine]

Pinging @elastic/infra-logs-ui

[jasonrhodes]

I updated the description, but FYI this work is blocked by elastic/elastic-charts#162

[markov00]

Hey @jasonrhodes what will be the optimal solution:

1. hide the upper and lower bound values on the tooltip
2. change the current behaviour and add the possibility to customize the tooltip names to upper/lower bounds?

[jasonrhodes]

@markov00 I'd say (2) is the more commonly needed solution (you probably want to tell people those bound values in most cases) but I can imagine wanting option (1) at times as well. Although that's more of a "how can I hide a series from the tooltip" question I think, which is applicable across all series imo.

[Kerry350]

Closing this specific Logs UI ticket as we're no longer rendering a band area chart for this data visualisation.