Pester Updates

[DeveloperDurp]

Modified the tests to check each entry in the applications.json file to ensure winget is defined. Same for each GUI checkbox. It will ensure an entry exists inside the json file. This will make it easier to pinpoint which application could be missing/not configured correctly.

I also removed all tests for the config files not implemented yet and tests should be a little more reliable now. Also modified the BranchToUse variable to only update on the main/test branch to make compatibility a little easier when working on forks.

Tried to find additional tests to do but didn't find any good candidates without needing to turn them into some sort of function.