The feature flag trackUnshardedCollectionsUponCreation is currently disabled in production. The code behind the fcv still requires to see the completion of SPM-3680, which won't make it for v9.0.

Meanwhile, the feature flag is still tested in the all-feature-flag build variant. 
Ideally, the feature flag can be disabled for the following reason:

• we are currently forcing developers to support code that won't be in production for many years
• It's currently known to cause a possible deadlock (SERVER-95544).

Fully disable the feature flag from being tested in the all-feature-flag variant. This is the first step to fix SERVER-95544