Catch and reissue fluview imputation errors as warnings to avoid failures

[nmdefries]

Summary:

Context

Imputed NY state data was not available because imputation failed on issue 2023w50. Of all states, only PR was reported for that issue, which caused an error to be raised. It isn't a bug -- the imputation code was set up to fail when the system (set of states) was all-missing, none-missing, or underdetermined (too many missing states to impute). Because the data is truly missing, we can't fix the root cause of the error or similar errors.

Instead, switch the errors to informational messages, but let imputation continue.

The imputation script should automatically fill all historical dates, so we won't need to patch this manually.

Closes #1388

Prerequisites:

• Unless it is a documentation hotfix it should be merged against the dev branch
• Branch is up-to-date with the branch to be merged with, i.e. dev
• Build is successful
• Code is cleaned up and formatted

[sonarqubecloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud