We need the ability to test the UI interactions in deploy

For instance, whether hitting escape cancels the deploy, or the handling of asking for parameters.

The package we use (@microsoft/vscode-azext-utils) is designed for this but I had trouble getting it set up last time I tried (to do with webpack and singleton usage).

Start by reviewing the @microsoft/vscode-azext-utils testing setup and the webpack singleton configuration that previously blocked adoption. Define coverage for Escape cancelling deployment and parameter prompts, with passing UI interaction tests as the completion criterion.

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