improve default command creation and messaging

[connectdotz]

The current default command is quite "shallow", which only looks for candidates in the current project root. And when it did not find it, it should have failed immediately but did not, which led to the process failure later.

deep search

In this PR, we will expand the existing logic by searching deeply from the workspace to find all possible subfolders (folders with package.json) and look for binary/test-script within. Basically, perform a deep auto-config for jest.rootPath and jest.jestCommandLine.

Note, auto-config is a best-effort, it might still require manual setup sometimes, such as:

• if this is a multi-root monorepo. From the project root, if we find multiple packages with valid jest commands, it can't be decided which one to use for the project root. This will still require converting to the multi-root workspace.
• yarn pnp will not work as it doesn't have node_modules. Maybe in the future PR we can provide native support for that.

There might be more, but now when the auto-config fails, users will see a clear message showing why jest command is not found, and has an opportunity to fix them (via the "Fix" button in the error panel), hopefully, easily.

favor test script over direct binary execution

This is a breaking change, if user has a jest test script in their package.json, we will use the script (either npm or yarn) instead of jest binary in node_modules.

overhead

This new feature does take a little bit more time at start-up time, but only for users who don't have a shallow jest command.

Notes for Future PRs

• we should add rootPath in the jestCommand setup wizard
• we should expand auto-config to include debugConfig (such as incorporating jestCommandLine) (Clicking on debug codelens throws MODULE_NOT_FOUND error (used with Yarn v3) #893)
• support pnp (Running "Jest: Setup Extension" doesn't work #827)

[coveralls]

Pull Request Test Coverage Report for Build 3545407489

• 120 of 120 (100.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 97.005%

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Totals
Change from base Build 3536361549:	0.01%
Covered Lines:	3273
Relevant Lines:	3315

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💛 - Coveralls