FIO-8954: added Allow only available values validation for Data Source Type = URL

[KatrinKhilko]

Link to Jira Ticket

https://formio.atlassian.net/browse/FIO-8954

Description

Added Allow only available values asynchronous validation for Data Source Type = URL. It fetches data from the URL and than compares values and provided data.

Breaking Changes / Backwards Compatibility

n/a

Dependencies

n/a

How has this PR been tested?

Added tests.

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

[brendanbond]

This seems like a lot of duplication of an existing validation rule, validateUrlSelectValue and, by extension, validateResourceSelectValue. Can your function replace, or be merged into, the already existing rules?

[brendanbond]

So does this replace the need for the two rule functions I mentioned previously? Or are select components handled in those and radios and select boxes in this new method? Sorry if I'm confused

Maybe best to discuss in dev support