fix(linter): noFloatingPromises detects "maybe" Promises

[arendjr]

Summary

Sometimes a statement resolves not just to Promise, but to Promise | undefined, or another union that includes a Promise. Such statements should be awaited too for proper handling, so noFloatingPromises will now trigger on those too.

Test Plan

Test case added.

[siketyan]

Nice!

[codspeed-hq]

CodSpeed Performance Report

Merging #6080 will not alter performance

_{Comparing arendjr:handle-maybe-promise (3f339ac) with main (64ca243)}

Summary

✅ 94 untouched benchmarks
🆕 1 new benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
🆕	html_formatter[index_1033418810622582172.html]	N/A	462.6 µs	N/A