Fix manual time entries storing with wrong timezone

[Gawdl3y]

Simply calling merge() on a FormRequest inside of passedValidation() doesn't update the validated data since a snapshot of the data is taken at the point of validation completing (before passedValidation() is called).

This PR:

• Updates the call to merge() to store the ISO 8601 timestamp so it's more "raw" just like if there were no merge call (although this has no consequence the way it's currently used)
• Overwrites the post-validation snapshot of the start and stop fields so the validated() call in the controller has the proper timezone

[travismolick]

When doing internal testing on what this fixes, it introduces a new bug which allows managers to be able to have a person have multiple clocked in times without forcing them to clock out a person, bypassing the check to prevent that.