FIO-8107: correct small error in normalize processor

[brendanbond]

Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-8107

Description

1. The normalize processor did not take into account falsy values for select boxes components. This has been corrected.
2. The normalize processor did not add to the scope object, this has also been corrected.
3. Tests

Breaking Changes / Backwards Compatibility

n/a

Dependencies

n/a

Checklist:

• I have completed the above PR template
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• My changes include tests that prove my fix is effective (or that my feature works as intended)
• New and existing unit/integration tests pass locally with my changes
• Any dependent changes have corresponding PRs that are listed above