chore: remove Pillow from dev dependency

[ptpt]

This pull request focuses on refactoring the unit tests for EXIF data handling by removing dependencies on the Pillow library and utilizing the ExifRead class for reading EXIF data. The main changes include the removal of Pillow from the requirements and test files, and the replacement of Pillow-based EXIF reading methods with methods from the ExifRead class.

Key changes include:

Dependencies:

• requirements-dev.txt: Removed Pillow from the list of dependencies.

Refactoring EXIF reading in tests:

• tests/unit/test_exifedit.py: Removed Pillow imports and related EXIF reading methods, replacing them with ExifRead class methods. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]

Refactoring EXIF reading tests:

• tests/unit/test_exifread.py: Removed Pillow imports and related EXIF reading methods, converting the tests to use ExifRead class methods and simplifying the test structure. [1] [2] [3] [4] [5] [6]