FIO-4871: Fixed calculated value for data grid component

[roma-formio]

Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-4871

Description

When the DataGrid component has the default 1st row, we can find some fields already have empty values in JSON. This is a reason why the calculated value doesn't apply for DataGrid with allow override. I tried to change this logic and save DataGrid with an empty array without nested fields. As a result, it caused a lot of tests to fail and can be an issue with the compatibility of existing forms. So I changed the isEmpty method for DataGrid to skip default empty fields and apply calculated value.

How has this PR been tested?

Unit testing

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