Update the Pymongo dependency

[feanil]

The pymongo dependency is pinned to an old version in base.in. Update the pin, update the output .txt files and fix any tests that break.

Newer versions may have breaking changes that may break upstream edx-platform so we should make sure to upgrade opaque keys and pymongo in edx-platform and fix any issues we encounter there as well as a part of this ticket.

[feanil]

FYI, the BOM team might be picking this up so coordinate with them if you're gonna be working on it.

[feanil]

Related edx-platform ticket that should be updated/closed when edx-platform is up-to-date: openedx/edx-platform#34586

[irtazaakram]

BOM squad is working on upgrading pymongo ref: openedx/edx-platform#34675

[farhan]

@feanil Please close it has PR has been merged.