Update num obs chip

[acholyn]

we're going to end up updating the metadata to show the actual number of observations, so we'll probably want to parse this to show a shorthand so the chip doesn't get super long

up to 999 is fine, then:
1000 and each 1000 after until 100k and then every 100k until 1 million: k (1k, 20k, 400k), for the interim numbers have a +
then 1m...