Problem Statement/Rationale

When using "mongosh --host mongodb+srv://connection string", --authenticationDatabase is not overriding the authSource if authSource is specified in the dns TXT records (guide https://docs.mongodb.com/manual/reference/connection-string/#dns-seed-list-connection-format)

We can override this when using mongodb NodeJS driver, but not when using shell.

Steps to Reproduce

create a connection seed list with "authSource=admin"

Expected Results

--authenticationDatabase "$external" should override the authSource in connection string.

Actual Results

Error returns MONGODB+X509  can only have authSource set to '$external'

Additional Notes

Applies to mongo and mongosh