Refactor: Move Cloud Functions logic to a dedicated service

[gino-m]

Refactored AuthService to delegate Cloud Functions related logic (sessionLogin and profileRefresh) to a new, dedicated CloudFunctionsService in order to improve code modularity. Replaced HttpClientService and Functions dependencies with CloudFunctionsService inside AuthService. Included unit tests for the new service and updated AuthService tests accordingly.

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PR created automatically by Jules for task 120037319741353196 started by @gino-m

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[gino-m]

@jules Please fix failing tests and try again.

[google-labs-jules]

@jules Please fix failing tests and try again.

I'm looking into the failing tests. I notice that trying to use spyOnProperty with httpsCallable gives not declared configurable. Is it possible to mock it using spyOn(fireFunctions, 'httpsCallable') instead in this CI setup, or by overriding httpsCallable with another method in the service that can be stubbed?