[Bug] Custom TokenValidationParameters.ValidAudiences is overwritten

[TiagoBrenck]

Which Version of Microsoft Identity Web are you using ?
preview

Where is the issue?

• Web App
  • Sign-in users
  • Sign-in users and call web APIs
• Web API
  • Protected web APIs (Validating tokens)
  • Protected web APIs (Validating scopes)
  • Protected web APIs call downstream web APIs
• Token cache serialization
  • In Memory caches
  • Session caches
  • Distributed caches

Other? - please describe;

Repro
As a developer, I might want to have my valid audience to be https://<tenantDomain> instead of api://<guid>.

For that I could use:

            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddProtectedWebApi("AzureAd", Configuration, options =>
                {
                    Configuration.Bind("AzureAD", options);
                    options.TokenValidationParameters.ValidAudiences = new List<string> { "https://<myTenantDomain>" };
                });

Expected behavior
Have the options.TokenValidationParameters.ValidAudiences set with my custom option.

Actual behavior
The method EnsureValidAudiencesContainsApiGuidIfGuidProvided() is overwriting my audiences in its logic.

Possible Solution
Have EnsureValidAudiencesContainsApiGuidIfGuidProvided() to extend my options and not overwrite it.

Additional context/ Logs / Screenshots
Add any other context about the problem here, such as logs and screenshots.

[jennyf19]

included in 0.1.1-preview release