For #70352

Uses `unknown` for parameters that we don't care about the type of. This prevents the type from being used incorrectly (which `any` would allow)

Investigating why these changes were required. Adding workarounds until then

* Load storage while loading renderer, not before (fixes #68400)

* storage - allow multiple init() calls

* adopt paths.node over path

* fix strict null

* remove hacky typing inlabel.test.ts

* Converted another ~70 test files to strictNullChecks

These are the remaining test files that didn't require any changes to non-test file types. I'll send those in separately.

Most changes were automatic and small (`!`s).
The only non-trival change is that `extHostSearch.ts` needs an interface for its test data.

Again used [TypeStat](https://github.com/JoshuaKGoldberg/TypeStat) when possible per #65581. I'm happy to split this up into smaller PRs if you'd prefer!

* Added missing `!`s to `commands.test.ts`

Use `Array<T | U>` when dealing with union types instead of  `(T | U)[]`

ES6 promises like using undefined as their first argument instead of null. Both should behave the same