New Description: The URI parser uses two variables per option: one for the value and one for determining if the option is set. This code that uses the parser is inconsistent. Sometimes, it checks the *Set variant but for some boolean options that are only useful if set to true (e.g. SSL), it will directly check cs.SSL rather than cs.SSLSet && cs.SSL. Let's refactor this to use pointers like the rest of our options code for consistency.

Previous Description: Pretty minor, but ConnString.SSLSet is never read by anything. I believe https://github.com/mongodb/mongo-go-driver/blob/a96725e2d7cb39d0c31f7f6605305ad3f92787c1/x/mongo/driver/topology/topology_options.go#L112 should actually be "if cs.SSLSet && cs.SSL {".