Refactor client to add guard clauses

[ZombieProtectionAgency]

Remove ~25% of whitespace by leveraging guard clauses Remove or replace several boolean literals
DRY out a few blocks of code
Correct some name casing inconsistencies

Sorry for such a minor change! I was just fiddling with the script myself to see what I might add/change and I refactored as I was messing with it. Since there haven't been changes to this repository in awhile I wanted to push my cleanup. If this looks Ok I will add on a similar cleanup for the server script.

• Have you personally loaded this code into an updated qbcore project and checked all it's functionality?
  • I did load and test the script though my testing was a little random.
• Does your code fit the style guidelines?
  • All categories of changes were based on existing code in the same project.
• Does your PR fit the contribution guidelines?
  • As far as I am aware my contribution does not violate any guidelines.

[Qwerty1Verified]

One reason I can think for this to be PlayerPedId() is that the skillbar minigame returns a promise meaning there could be some fair time difference between the definition of ped and the logic utilising it running.

I feel as though in edge cases like the local ped handle changing in-between the minigame starting, and finishing, there could be unexpected behaviour. This is certainly just a negligible edge case though. Realistically, since this condition is solely for if the player is lockpicking from within the seat, their ped handle changing (new ped) should lead to them being kicked out of the vehicle anyways.