[candidate_parameters] use DoB and DoD format

[CamilleBeau]

Brief summary of changes

This PR uses the DoB and DoD format from configuration in the DoB and DoD tabs respectively.

• Have you updated related documentation?

Testing instructions (if applicable)

1. Modify the DoB and DoD format in the configuration module
2. Make sure that these formats are respected in their respective tabs in the candidate parameters module
3. Try saving the DoB and DoD in each new format, make sure it saves properly and loads properly
4. Make sure to test on candidates with and without DoB and DoD

Link(s) to related issue(s)

• Resolves [Candidate parameter] DoB and DoD formats ignored #6994

[miladheshmati]

Code looks good

[miladheshmati]

When I am trying to submit a change in the configuration module, this 404 error appears:

[CamilleBeau]

@miladheshmati I don't think this is related to this PR? I'm only modifying candidate parameters here