feat(NODE-4243): drop collection checks ns not found

[durran]

Description

Dropping collections will no longer fail when the namespace isn't found.

Summary of Changes

• Updates collection.drop() to return false if a ns is not found.
• Updates all locations in the driver that implemented this logic.

Notes for Reviewers

The AC on the ticket said to only update behaviour in the unified runner, but I took this opportunity to pull it out everywhere.

What is the motivation for this change?

NODE-4243

Release Highlight

Dropping a Collection No Longer Throws When NS not Found

This will now return false instead.

Double check the following

• Lint is passing (npm run check:lint)
• Self-review completed using the steps outlined here
• PR title follows the correct format: type(NODE-xxxx)[!]: description
  • Example: feat(NODE-1234)!: rewriting everything in coffeescript
• Changes are covered by tests
• New TODOs have a related JIRA ticket

Addressed