Changing Pack resolution after a world has been loaded does not work

Verification builds: 1.5.0.14_RC (1001349 - Release)

Summary: If you loaded a world with a specific resolution (for packs with multiple resolutions), you can't change that resolution without a game restart.

Impact: Users think they are playing with the subpack/resolution they selected while they are playing with the previously selected one.

Repro Steps:

1. Download and import PureBDcraft
2. Select 32x in resolutions
3. Load a world
4. Save and Quit
5. Change resolution of PureBDcraft in its settings to 128x
6. Load a world
7. See that you are still with 32x and not 128x

Observed Results: Wrong subpack/resolution in game instead of the selected one.

Expected Results: The loaded game should run on the selected subpack/resolution of the ResourcePacks in settings.

Screenshots/Videos attached: No.