fix(helix): allow querying moderator status of multiple user ids

[iProdigy]

Prerequisites for Code Changes

• This pull request follows the code style of the project
• I have tested this feature

Issues Fixed

• TwitchHelix#getModerators would fail when passed more than one user ID to check moderator status (Twitch would complain about malformed query parameter)

Changes Proposed

• Use repeated query param format for userIds in TwitchHelix#getModerators instead of CSV format

Additional Information

Typically people query all mods (i.e., pass null for userIds) or check for a single user ID, so this issue hadn't been noticed