Run tests / chore: Enable nullable annotations for part of the files (#2986) * chore: enable nullable * chore: fix wrong nullable annotations * chore: remove redundant comment that contains typo * chore: fix indents and null comparison

Run tests / chore: Enable nullable annotations for part of the files (#2986) * chore: enable nullable * chore: fix wrong nullable annotations * chore: remove redundant comment that contains typo * chore: fix indents and null comparison #2337