IBX-9727: Added typehints and adapted forms-related code to PHP8

[konradoboza]

🎫 Issue	IBX-9727

Description:

Regressions build: ibexa/commerce#1487 ✅

For QA:

Documentation:

[adamwojs]

I would be more conservative with adding final keyword to existing classes but overall changes looks good.

[konradoboza]

I would be more conservative with adding final keyword to existing classes but overall changes looks good.

Well, all of the form data-classes should be final in the first place unless they are extended in the child classes. I added it whenever possible without breaking things. We don't keep any BC promise on form data classes shape, so in my opinion they shouldn't be extended.

Form-based extension points should be relying on form extensions and decorating data classes. If you have any specifics in mind, please let me know so we can revert per-case-basis @adamwojs.

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
1.5% Duplication on New Code

See analysis details on SonarQube Cloud