fix: Correctly handle TLS config when ssl=true or tls=true connection string option set.

[cyrus-mc]

fix for #9509

Merge writeOpts and authOpts after call too ApplyURI.

[hashicorp-cla]

All committers have signed the CLA.

[cyrus-mc]

Build is failing with error about using internal module. This PR doesn't touch any of that (it is a simple one line change) so not sure how this error is being caused.

[cyrus-mc]

@ncabatoff Merged in latest master changes that fixed build. This PR is ready to go. I am using a locally build Vault, containing this fix, without issue.

[ncabatoff]

Thanks @cyrus-mc!

[pbar1]

Hey, FYI - this change seemed to break our Mongo secret engine upon upgrading Vault from 1.5 -> 1.6. When setting up the provider, we use client TLS as well as the username/password authentication via SCRAM-SHA-256. Due to the order in which this change merges config, if client TLS configuration is passed, the MongoDB x.509 auth mechanism will always win; this renders other auth mechanisms unusable.