chore: v1 implementation of admin and assembly condition stubs

[jacobrkerstetter]

Description

As title says

Issue linked

Related to #2388

Checklist

• I have tested my changes locally.
• I have added necessary documentation or updated existing documentation.
• I have followed the coding style guidelines of this project.
• I have added appropriate unit tests.
• I have reviewed my changes before submitting this pull request.
• I have linked the issue or issues that are solved to the PR if any.
• I have assigned this PR to myself.
• I have added the minimum version decorator to any new backend method implemented.
• I have made sure that the title of my PR follows Conventional commits style (e.g. feat: extrude circle to cylinder)

[codecov]

Codecov Report

❌ Patch coverage is 50.74627% with 33 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.98%. Comparing base (454f13e) to head (636bb90).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ys/geometry/core/_grpc/_services/v1/conversions.py	20.83%	19 Missing ⚠️
...etry/core/_grpc/_services/v1/assembly_condition.py	48.14%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2391      +/-   ##
==========================================
- Coverage   95.21%   94.98%   -0.24%     
==========================================
  Files         168      169       +1     
  Lines       11290    11327      +37     
==========================================
+ Hits        10750    10759       +9     
- Misses        540      568      +28     

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[RobPasMue]

Small comment but LGTM!