fix(eslint-plugin): [no-unnecessary-type-assertion] correct handling of undefined vs. void#11826

JoshuaKGoldberg merged 5 commits intotypescript-eslint:maintypescript-eslint/typescript-eslint:mainfrom

Tamashoo:fix/no-unnecessary-type-assertion-iife-caseTamashoo/typescript-eslint:fix/no-unnecessary-type-assertion-iife-caseCopy head branch name to clipboard