Add `npm run ava` command, update instructions, and exclude files from VSCode search #7886

Job	Run time
Packaging: Action input (windows-latest, default)	4m 4s
Packaging: Action input (macos-latest, linked)	2m 8s
Packaging: Action input (ubuntu-latest, default)	1m 30s
Packaging: Action input (ubuntu-latest, nightly-latest)	1m 26s
Packaging: Action input (ubuntu-latest, linked)	1m 34s
Packaging: Action input (macos-latest, nightly-latest)	1m 46s
Packaging: Action input (macos-latest, default)	2m 31s
Packaging: Action input (windows-latest, nightly-latest)	5m 34s
Packaging: Action input (windows-latest, linked)	4m 2s
	24m 35s

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