Implement client-side function to recombine partial-exit blobs (recombineExitBlobs)

[LukeHackett12]

Create a client-side function, recombineExitBlobs, to stitch together a list of valid partial-exit blobs into a full exit message. Note: The same approach is intended for both solutions. [TO DO] Check with Luke/Kalo regarding the link they shared for this logic to confirm the implementation details.