Fixed Users API update from clearing location_id unnecessarily

[Godmartinz]

Description

This makes updating the location_id conditional only if the location_id key is passed in the PATCH or PUT request (even though you shouldn't use a PUT request most of the time).

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• [ x] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• PHP version:
• MySQL version
• Webserver version
• OS version

Checklist:

• I have read the Contributing documentation available here: https://snipe-it.readme.io/docs/contributing-overview
• I have formatted this PR according to the project guidelines: https://snipe-it.readme.io/docs/contributing-overview#pull-request-guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[what-the-diff]

PR Summary

• Improved Location Update
  This update adds a condition that must be met before the location of items assigned to a user gets modified. This means the system will first confirm there is a 'location_id' present in the request before changing any location data. This act ensures more accurate and reliable location updates.

[snipe]

Awesome, ty!

[snipe]

@Godmartinz can you retarget this to develop tho? ;)

[Godmartinz]

done 👍