feat: add noElectronStart CLI option to the dev command

[erikian]

Description

This adds an option to not start the Electron app after the dev server is up.

Additional context

The main motivation is being able to run Playwright tests faster; this would make it possible to use electron-vite to run the dev server and configure Playwright to run in development mode using that server, instead of having to bundle the entire project beforehand (which takes too long if you just want to run a one-off test to validate the code you're currently working on).

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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