Adds Validation for status label creation through the API

[Godmartinz]

Description

Validation check:

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• [x ] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

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
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• 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

• Enhanced Error Message Customization in Status Labels
  The update in StatuslabelsController.php allows for the specific error message "Status label type is required" to be translated into different languages, thus improving the adaptability of the application to various user language preferences.

• New Translation String for Status Label Requirement
  A new translation string has been incorporated in the message.php file, particularly for the "Status label type is required" message, enabling easy conversion of this instruction into other languages.

[snipe]

As I mentioned in the previous PR, why aren't we just using normal validation here? If we were, we'd get that for free without having to translate it.

[Godmartinz]

Validation added, and translation removed. 👍

[snipe]

I think if we do it this way, we're not actually checking for type though, no? We don't have that constraint in the model $rules:

    protected $rules = [
        'name'  => 'required|string|unique_undeleted',
        'notes'   => 'string|nullable',
        'deployable' => 'required',
        'pending' => 'required',
        'archived' => 'required',
    ];

since type isn't an actual field on the table.