testing setup polish: uncomment and submodule fix for branch still needed

[hanbollar]

          ### lingering notes:

• https://github.com/Volumetrics-io/mrjs/pull/607/files#diff-2044058842a4c83fc7d73ef7c71f5fdbb8fcee1f0af077ecd6b0ca6341ffcfe2R26-R29

^ this is causing extra errors to occur, for ex: MRSystem not existing, even though it does, just not in the puppeteer setup at that time -- these are only erroring due to an improper testing setup, so commenting it out - to noodle on a little still

• scripts/check-and-update-submodule.sh only runs nicely on main, not a branch

going to open an issue based off this to resolve, but not a high priority

Originally posted by @hanbollar in https://github.com/Volumetrics-io/mrjs/issues/607#issuecomment-2091872418

[hanbollar]

assigning to self, but these two items are not priority atm