Alignement with Spring25

[bigludo7]

What type of PR is this?

Add one of the following kinds:

• enhancement/feature

What this PR does / why we need it:

See #87

Which issue(s) this PR fixes:

Fixes #85 #86 #87 #88

Special notes for reviewers:

Changelog input

 release-note
- Make phoneNumber optional in send-code (no change for the consumer)
- Align x-correlator definition (no change for the consumer)
- Remove from the yaml the errors 406, 415, 500, 503 & 504 (no change for the consumer)
- Remove test cases for 406 & 415 (no change for the consumer)
- Restructure test cases (no change for the consumer)
- Fix test cases @OTPvalidationAPI_02_send_code_success_scenario_without_x-correlator and @OTPvalidationAPI_02_validate_code_sucess_scenario_without_x-correlator (no change for the consumer)
- Change error structure as defined in commonalities 0.5.0 (no change for the consumer)

Additional documentation

This section can be blank.

docs

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ ACTION	actionlint	2		0	0.03s
✅ OPENAPI	spectral	1		0	1.73s
✅ REPOSITORY	git_diff	yes		no	0.01s
✅ REPOSITORY	secretlint	yes		no	0.75s
✅ YAML	yamllint	1		0	0.35s

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[bigludo7]

@fernandopradocabrillo @jgarciahospital Accordingly to our discussion in #88 I've updated the yaml & Test Case.
Fernando if you can proceed to a last review to check if we're good. Thanks !