[BUG] Mirth Client Crashes when doing a Test Write on File Writer with no value in Directory field

[mgaffigan]

Describe the bug
Mirth Client Crashes when doing a Test Write on File Writer with no value in Directory field and Mirth 3.12 running inside of a container.

To Reproduce
Create a channel and set destination to File Writer
Click Test Write

Expected behavior
Not crash and given an error.

Actual behavior
An unexpected error occurred. Full message

Related
Originally #4963
Summary #121

[david-labs-ca]

Maybe an empty check in missing in FileConnector.java getEndpointURI method.

However, why would someone test write an empty directory?