Fixing data processing issue

This PR:

Fixes an issue seen with one user in the remove_special_chars function
- Before this PR, the function would return TypeError: argument of type 'float' is not iterable
- After this PR, the function sets two invalid rows to have an empty string value
Renames the automated continuous integration (CI) tests as DataKind New America Housing Tool CI
Adds a test for the modified remove_special_chars function

datakind / new-america-housing-loss-public