Detailed steps to reproduce the problem?

Previous go driver versions were able to connect via UNIX sockets formatted like this:
mongodb://%2Ftmp%2Fmongodb-27017.sock/database?connectTimeoutMS=1000&directConnection=true&serverSelectionTimeoutMS=1000

Recently, this seems to be broken and now gives this error:
parse "mongodb://%2Ftmp%2Fmongodb-27017.sock/database?connectTimeoutMS=1000&directConnection=true&serverSelectionTimeoutMS=1000": invalid URL escape "%2F"

I think it could be related to the URL parsing that was added in this commit https://github.com/mongodb/mongo-go-driver/pull/1373/files#diff-f8f709cd4fe1c51ef99b7a9731b69373e4e4119ebfdeca319763200b30e8dec4

Definition of done: what must be done to consider the task complete?

Clients can be connected successfully via UNIX sockets

The exact Go version used, with patch level:

$ go version

The exact version of the Go driver used:

$ go list -m go.mongodb.org/mongo-driver

Describe how MongoDB is set up. Local vs Hosted, version, topology, load balanced, etc.

The operating system and version (e.g. Windows 7, OSX 10.8, ...)

Security Vulnerabilities

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