Fix nodestate remove for diagnostic infos

[mregen]

Proposed changes

Issue:

• In order to fix Possible memory leak if a Node is removed after a session is closed. #2343, the change caused a regression pointed out by NodeState.RemoveReference may remove the wrong reference #2446.

Fix:

• First try to remove node, only then try to remove the reference to the target node.

Repro:

• connect/disconnect to the server with diagnostics enabled. Check Diagnostic nodes for leaking references.

Related Issues

• Fixes NodeState.RemoveReference may remove the wrong reference #2446 , Possible memory leak if a Node is removed after a session is closed. #2343

Types of changes

What types of changes does your code introduce?
Put an x in the boxes that apply. You can also fill these out after creating the PR.

• 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

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• 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: 5 lines in your changes are missing coverage. Please review.

Comparison is base (e49ae09) 45.56% compared to head (0f446c4) 53.73%.

Files	Patch %	Lines
Stack/Opc.Ua.Core/Stack/State/NodeState.cs	44.44%	1 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2450      +/-   ##
==========================================
+ Coverage   45.56%   53.73%   +8.16%     
==========================================
  Files         333      333              
  Lines       64341    64329      -12     
  Branches    13203    13200       -3     
==========================================
+ Hits        29320    34569    +5249     
+ Misses      31547    26000    -5547     
- Partials     3474     3760     +286     

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