dillon1000/react

run SchedulerFeatureFlags with variant flags again (#26851)

With df12d7eac40c87bd5fdde0aa5a739bce9e7dce27 I accidentally made it so
that tests aren't run with the 2 variant modes for most
SchedulerFeatureFlags anymore. This fixes it with the same approach as
ee4233bdbc71a7e09395a613c7dde01194d2a830.

Test Plan:
Run and notice the boolean flags follow the variant:
```
yarn test-www --variant=true
yarn test-www --variant=false
```