Set the height of each row in the measurements panel based on number of measurements displayed

[huddlej]

Description

Set the height of each row in the measurements panel to match the number of measurements displayed. @jameshadfield's original comment about this functionality, he recommended:

having layout.subplotHeight depend on the number of measurements in the group (perhaps with some ceiling)

@joverlee521 noted:

On one hand, it would be a great way to save space within the viz. On the other hand, this also visually devalues the groups that have less measurements. Maybe that's something we want?

In the original suggestion, each row would have a different height depending on the number of measurements shown in that row.

@huddlej's alternate suggestion is to rescale the height of all rows to match the max number of measurements (in raw display) or measurement colorings (in mean/std display). A major difference here is that all rows have the same height, allowing users to compare the same within-row y-axis positions between rows (e.g., comparing the same clade's test measurements between different reference strains). This implementation would shrink or increase the vertical space to the minimum necessary based on the data displayed (in a y-axis version of #1814). This feature would better account for an increase in the number measurements display when the user sets the coloring to a field that has many values. When the number of colorings increases in the current implementation, colors within each row get plotted on top of each other and can even run off the top or bottom of the row in extreme cases. The following example from the measurements panel dataset shows a coloring by genotype at 5 HA1 sites where this overlapping happens