fix: cache items only when coming from trusted proxy

[achmelo]

Description

Caching service allows to store items under the arbitrary value in header if the request is authenticated with client certificate. This change makes the validation more strict and allow to items only when the request is coming from a trusted proxy. It also drops support for custom header and keeps only standard Client-Cert header.

Linked to #4651

Type of change

• fix: Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project
• PR title conforms to commit message guideline ## Commit Message Structure Guideline
• I have commented my code, particularly in hard-to-understand areas. In JS I did provide JSDoc
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• The java tests in the area I was working on leverage @nested annotations
• Any dependent changes have been merged and published in downstream modules

[pablocarle]

Please update the title the of PR.
Most questions can be out of ignorance, take them with a grain of salt

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
82.6% Coverage on New Code
1.7% Duplication on New Code

See analysis details on SonarQube Cloud