[Server] [Client] Return BadIdentityTokenInvalid if use of anonymous identity token is not allowed

[romanett]

Proposed changes

Return StatusCode.BadIdentityTokenInvalid instead of BadUserAccessDenied if the Client sends an AnonymousIdentityToken or no identity Token at all. This makes the Server pass UA CTT SessionService -> SessionBase -> TestCases -> Err-009

Make the Client throw a ServiceResultException BadIdentityTokenInvalid instead of BadUserAccessDenied to be consistent with the response a server would send. This is relevant as our client does a "pre-check" if the endpoint supports the provided policy before sending the request to the server

Related Issues

• Fixes Unsupported anonymous UserIdentity response discrepancy from UACTT expected result #3001
• Fixes BadUserAccessDenied when the Identity token provided is not in the list of the server #2900

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• [] Enhancement (non-breaking change which adds functionality)
• Test enhancement (non-breaking change to increase test coverage)
• Breaking change (fix or feature that would cause existing functionality to not work as expected, requires version increase of Nuget packages)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc.
• I have signed the CLA.
• I ran tests locally with my changes, all passed.
• I fixed all failing tests in the CI pipelines.
• I fixed all introduced issues with CodeQL and LGTM.
• I have added tests that prove my fix is effective or that my feature works and increased code coverage.
• I have added necessary documentation (if appropriate).
• Any dependent changes have been merged and published in downstream modules.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 55.73%. Comparing base (38388f1) to head (06519fb).
Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
Libraries/Opc.Ua.Client/Session/Session.cs	0.00%	1 Missing ⚠️
Libraries/Opc.Ua.Server/Session/Session.cs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3012      +/-   ##
==========================================
+ Coverage   55.69%   55.73%   +0.04%     
==========================================
  Files         352      352              
  Lines       67926    67907      -19     
  Branches    13939    13918      -21     
==========================================
+ Hits        37829    37850      +21     
+ Misses      25948    25915      -33     
+ Partials     4149     4142       -7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.