Fix docker build

[rbnswartz]

This pull request updates the Docker build GitHub Actions workflow to modernize dependencies, streamline the build and push process, and improve maintainability. The workflow now uses newer versions of actions, consolidates build and push steps, and introduces dynamic Docker image tagging.

Workflow modernization and simplification:

• Updated action versions to the latest (actions/checkout@v4, docker/setup-qemu-action@v3, docker/setup-buildx-action@v3, docker/build-push-action@v6, etc.) and consolidated the build and push steps into a single build-and-push job for clarity and maintainability.
• Replaced manual tag and label management with the docker/metadata-action@v5, enabling dynamic tagging based on branch, commit SHA, and the master branch.

Secrets and authentication improvements:

• Updated the 1Password secrets action to v4 and improved secret loading logic, ensuring Docker Hub credentials are only loaded and used on push events.
• Upgraded Docker Hub login to use docker/login-action@v3 and made the login conditional on push events for better security and efficiency.

Build process enhancements:

• The Docker image build now uses the latest `build-p

[Copilot]

Pull request overview

Updates the GitHub Actions Docker workflow to reliably build the .NET image on PRs while only authenticating and pushing to Docker Hub on branch pushes.

Changes:

• Consolidates build/push logic into a single build-and-push job with conditional Docker Hub login and push.
• Updates GitHub Actions and Docker actions to newer major versions (checkout, buildx/qemu, login, build-push).
• Replaces custom tag scripting with docker/metadata-action for consistent tags/labels.

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