Tsconfig no unchecked index access streams ts

[brentguf]

@luucvanderzee check carefully I didn't make mistakes because this is a critical file. :-) Might also run tests on this.

[cl-dev-bot]

	Warnings
:warning:	The branch name contains no Jira issue key (case-sensitive)
:warning:	The PR title contains no Jira issue key (case-sensitive)
:warning:	The changelog hasn't been modified

Generated by :no_entry_sign: dangerJS against 1905334d2879e28b3ef6a38f480c53a11a784315

[luucvanderzee]

I am wondering if with these kind of checks we should have some fallback behavior? Like maybe a console.error? Because now maybe we don't get a runtime error because of the indexing access returning undefined, but we might still generate other runtime errors / strange behavior downstream. Adding an explicit error log will make such situations easier to debug.