#26741: [desktop] Update the project python bootstrap to reset PATH

Make sure applications are launched with the proper DllDirectory set.
It really depends on your point of view. A state is pushed, and it is then popped. Now what may be confusing, is one of the actions of pushing the state actually pops another one. Personally I think it's ok, but I can see where the confusion comes from. Instead of seeing it a 'we're popping the DLL folder', just think of it as 'we're pushing the current dll folder and clearing it'.