fix(eslint-plugin): [no-throw-literal] support type assertions

[cherryblossom000]

Fixes #2350

[typescript-eslint]

Thanks for the PR, @cherryblossom000!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

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.

Thanks again!

---

🙏 Please, if you or your company is finding typescript-eslint valuable, help us sustain the project by sponsoring it transparently on https://opencollective.com/typescript-eslint. As a thank you, your profile/company logo will be added to our main README which receives thousands of unique visitors per day.

[codecov]

Codecov Report

Merging #2354 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2354   +/-   ##
=======================================
  Coverage   93.10%   93.10%           
=======================================
  Files         285      285           
  Lines        9125     9125           
  Branches     2504     2504           
=======================================
  Hits         8496     8496           
  Misses        302      302           
  Partials      327      327           

Flag	Coverage Δ
#unittest	93.10% <ø> (ø)

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

Impacted Files	Coverage Δ
...ckages/eslint-plugin/src/rules/no-throw-literal.ts	96.07% <ø> (ø)

[bradzacher]

LGTM - thanks for this!