Change missing value in satbias converter

[CoryMartin-NOAA]

Description

OOPS missingValue was changed, and thus broke ioda-converters. This PR should fix that.

Issue(s) addressed

Resolves #1403 1403

Dependencies

Impact

Checklist

• [x] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [ ] I have run the unit tests before creating the PR

[fmahebert]

Thanks for this fix, @CoryMartin-NOAA