fix OOC: PPM should be constant with haste

[lime-green]

https://classic.warcraftlogs.com/reports/J7N3nyDMBWRjYZCK#boss=-3&difficulty=0&source=1&type=casts

User told me they had 709 haste:

3000 / (1+709/3279) = 2466


You had 50.7% Nature's Grace uptime on your log:
3000 / ((1+(709+340*0.1739)/3279)*(1+0.2*0.507)) = 2206


Calculating expected OOC proc rate:
(2.206 / 60) * 3.5 * 0.666 = 0.086


Log Proc Rate:
151 / 2,015 = 0.0749

checks out

95% CI is 1.1%, a bit off but nature's grace calc is napkin-y and would have higher uptime bc/ it would apply for the full cast even if it falls off during the cast. If PPM wasn't constant with haste we would see:

(3 / 60) * 3.5 * 0.666 = 0.11655

clearly isn't right