Make number of new jobs optional for FDI projects with no involvement

[peterhudec]

Description of change

This PR makes the number of new jobs field in the edit project values form optional for all FDI projects with no level of involvement.

Test instructions

1. Create a new investment project with
   • Investment type = FDI -> [whatever] and
   • Level of investor involvement = No Involvement
     Or find an existing project with the above properties and grab its ID
2. Navigate to /investments/projects/{project-id}/edit-value
3. There should be a Number of new jobs (optional) field
4. You should be able to leave the field empty or put 0 into it as a value
5. Upon submitting the form, there should be no form error related to that field
6. Change the Level of investor involvement of the project to any value other than No Involvement
7. Now the field should be required and have a label Number of new jobs (required)
8. If you leave the field empty or put 0 into it as a value and submit the form
9. You should see a form error related to the field saying that the field is required or that the value must not be 0

[cypress]

data-hub-frontend    Run #60553

Run Properties:   Passed #60553  •  1d3629ba4c: Removed commented out code

Project	data-hub-frontend
Branch Review	feat/optional-jobs-on-fdi-projects
Run status	Passed #60553
Run duration	09m 11s
Commit	1d3629ba4c: Removed commented out code
Committer	Peter Hudec
View all properties for this run ↗︎

---

Test results
Failures	0
Flaky	0
Pending	4
Skipped	0
Passing	74
View all changes introduced in this branch ↗︎

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.09%. Comparing base (47d9aab) to head (1d3629b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7702      +/-   ##
==========================================
+ Coverage   89.90%   90.09%   +0.19%     
==========================================
  Files        1151     1151              
  Lines       17812    17807       -5     
  Branches     5167     5165       -2     
==========================================
+ Hits        16014    16044      +30     
+ Misses       1798     1763      -35     

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