fix(GuildEmojiRoleManager): bug in #remove

[iShibi]

Please describe the changes this PR makes and why it should be merged:

This PR fixes a bug in GuildEmojiRoleManager#remove, where it wasn't removing role(s) from the emoji. This bug was a result of an oversight in #5314. Since, #keyArray is being used there on this._roles collection, the role is already an ID, doing role.id returns undefined which results in newRoles containing IDs of the roles the emoji already has. This means no filtration happened and Discord got role IDs that were already on the emoji. Therefore, the role a user wants to remove from the emoji doesn't get removed.

ℹ️: Even tho the fix could be done by just changing role.id to role, I did some refactoring by renaming some identifiers in the #remove method so that oversight like this doesn't happen again. I noticed that some other methods also need this refactorization in GuildEmojiRoleManager file. I didn't do it in order to keep the initial review of the PR easy. Let me know If I should do it or not in this PR.

Status and versioning classification:

• Code changes have been tested against the Discord API
• I know how to update typings and have done so, or typings don't need updating

[ckohen]

I was asked to leave the name resolvedRoles in the original PR, not 100% sure why, may have been a consistency thing. I'm all for the change though.