Currently, there is no indication of what's going on or what is the process stage percentage-wise after executing the setFeatureCompatibilityVersion command.

It would be useful to have a ProgressMeter similar to what we have for index build: https://github.com/mongodb/mongo/blob/d52125a29a1e98e85b0fb1a68e3a93537fef1414/src/mongo/db/catalog/multi_index_block.cpp#L404 while periodically yielding the progress to the log.