[Stats Refresh] Correct number formatting on Chart axes

[ghost]

With #11061, we constructed a chart with some stub data to match Zeplin. The formatting here is not currently locale-sensitive, nor does it match the formatting applied elsewhere in Stats.

In paCL20-3g-p2, however, we have obtained confirmation that this behavior should differ. So rather than transition to use the existing Double+Stats, we will improve the placeholder to account for broader ranges and improve locale support.

It's worth noting that our Woo colleagues have noted similar requirements both here and here.