bump mongo java driver to 3.8.2 (#12200)
bump mongo java driver to 3.8.2 (#12200)

Picking up a few bug fixes that may or may not be impacting us,
see release notes here: https://github.com/mongodb/mongo-java-driver/releases
(sapling split of c250ca6038bfef287aeb4b66acbcd8ba8fd219b0)
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