Improve importer tests

[marcusmoore]

Description

This PR builds on top of the great work by @bryanlopezinc in #15579

Included:

• minor typo fixes
• swapping assertEquals from ($actual, $expected) to ($expected, $actual)
• simplifying permission tests
• migrating factory usage to our "normal" syntax
• and importantly, cleaning up the import files that the tests generate

Marking as draft because I'm going to give it another look over.
(Also waiting for #15603 to be merged)

Type of change

• Tests

[what-the-diff]

PR Summary

• Updated Import Model: The Import model in our software has been upgraded with an additional feature (HasFactory trait). This should increase its efficiency and capacity to handle data.

• Adjustment within Import Factory:

  • We've edited certain categorizations; for instance, 'Accessories' is now recognized as 'accessory' during the import process.
  • We've also refined how we build the ComponentsImportFileBuilder, which should result in more accurate data handling.

• Enhanced Testing Procedures:

  • We've initiated a new file (GeneralImportTest) to better monitor and verify the import procedures specific to accessory types.
  • The existing ImportDataTestCase has been streamlined (use Tests\TestCase;). The redundant permissions test data has been eliminated from the system.

• Special Care Post-Testing: We've introduced a feature (CleansUpImportFiles trait) that automatically clears up leftover files once the tests have been conducted. This should keep the system efficient and clutter-free.

[marcusmoore]

@snipe this is ready for review but needs #15603 to be merged first.