fix(eslint-plugin): added safe getTypeOfPropertyOfType wrapper

[JoshuaKGoldberg]

Fixes #2143. A quick find-all on getTypeOfPropertyOfType showed that the bug might also be able to pop up in no-unnecessary-condition as well.

[typescript-eslint]

Thanks for the PR, @JoshuaKGoldberg!

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The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

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[bradzacher]

We should add a lint rule for this to warn against using the method directly.

Could expand this internal lint rule to cover it:

https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin-internal/src/rules/no-poorly-typed-ts-props.ts

[JoshuaKGoldberg]

TBD whether this original approach works, but it would also be nice to not use an internal TypeScript compiler API... I'd be interested in looking at that too.

[codecov]

Codecov Report

Merging #2567 into master will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2567      +/-   ##
==========================================
- Coverage   92.82%   92.82%   -0.01%     
==========================================
  Files         290      291       +1     
  Lines        9505     9514       +9     
  Branches     2664     2666       +2     
==========================================
+ Hits         8823     8831       +8     
  Misses        323      323              
- Partials      359      360       +1     

Flag	Coverage Δ
#unittest	92.82% <ø> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...slint-plugin/src/rules/no-unnecessary-condition.ts	97.14% <ø> (ø)
packages/eslint-plugin/src/util/isTypeReadonly.ts	97.01% <ø> (ø)
packages/eslint-plugin/src/util/propertyTypes.ts	88.88% <ø> (ø)

[bradzacher]

LGTM - thanks for fixing this!