Quick: Avoid DataFilesSystemSelector test error

[wesleyboar]

Overview:

Avoid console error from DataFilesSystemSelector on npm run test.

Warning: value prop on select should not be null. Consider using an empty string to clear the component or undefined for uncontrolled components.

PR Status:

• Ready.

Related Jira tickets:

• N/A

Summary of Changes:

• Fix (?): Default to empty string if value is null.*

* Setting to undefined also removes the error—considered because "empty string is a valid option value" so maybe it should not be a fallback—but I blindly opted to do what the error message said.

Testing Steps:

1. Run npm run test.
2. No console error.

UI Photos:

N/A

Notes:

The reference I found on the issue was an issue complaining about the messaging and a PR to improve the error messaging which still can sometimes mention empty string as the solution.

[codecov]

Codecov Report

Merging #262 (6f77ee5) into master (73a8c4b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #262   +/-   ##
=======================================
  Coverage   60.10%   60.10%           
=======================================
  Files         315      315           
  Lines        9707     9707           
  Branches     1517     1517           
=======================================
  Hits         5834     5834           
  Misses       3609     3609           
  Partials      264      264           

Flag	Coverage Δ
javascript	60.82% <ø> (ø)
unittests	59.67% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...DataFilesSystemSelector/DataFilesSystemSelector.js	75.00% <ø> (ø)

[jarosenb]

LGTM!