Changes

Update `ChunkTag`, `AreaContainmentObject` and `ColorTag` tag param usage. (#2364)

* Update tag param usage for `ChunkTag`

Contributes to issue #2355.

* Update tag param usage for `AreaContainmentObject`

Contributes to issue #2355.

* Update tag param usage for `<ColorTag.mix[]>`

Contributes to issue #2355.

* Remove `null` checks in a few `AreaContainmentObject` tags.

New tag processing makes sure the parameter is valid as pointed out by @tal5!

* Remove `null` check in `<ColorTag.mix[]>`
 (commit: 16e64a5)