Incomplete argument validation in SnowflakeIO

Hi.

I noticed that the validation of arguments from users is not complete, which sometimes leads to problems that are difficult to troubleshoot:
- The server name or address must be specified, but it is not checked.
- We have validation for multiple arguments, but only checks if the builder method was called, but the value can still be empty as we use ValueProvider in multiple places.

Best regards,
Kamil

Imported from Jira [BEAM-14215](https://issues.apache.org/jira/browse/BEAM-14215). Original Jira may contain additional context.
Reported by: sfc-gh-kbregula.