Remove redundant dotnet build step from build workflow

[Copilot]

dotnet publish implicitly builds the project, making the preceding dotnet build step redundant.

Changes

• Removed dotnet build from the workflow step
• Renamed step from "Build & package with dotnet" to "Publish with dotnet"

Before:

- name: Build & package with `dotnet`
  run: |
    dotnet build -c Release --verbosity q --nologo
    dotnet publish --configuration Release --verbosity q --nologo

After:

- name: Publish with `dotnet`
  run: dotnet publish --configuration Release --verbosity q --nologo

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