fix(Permissions): toArray shouldn't check admin

[DTrombett]

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

When a member is an administrator, he does have all permissions but it's still possible to add/remove other permissions. Although it doesn't have any effect, the bitfield is still different and the toArray() method should return the permissions of the bitfield.
This can be done by passing false to the toArray() call.
This change also resolves #6267, which seems a regression added in #5911.

I've also considered defaulting the checkAdmin parameter to false in Permissions#toArray() but it would be inconsistent with other methods and useless as I don't see any use case where an array with all the flags is needed for an administrator and could be confused with a person with really every permission.

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating

[kyranet]

We seriously need to make unit tests for this, it's a really troublesome class.