PTHMINT-87: Fix ruff D103

[zulquer]

This pull request mainly adds docstrings to pytest fixtures and test functions across multiple test files to improve code documentation and clarity. Additionally, it makes a small configuration change to the pyproject.toml file related to linting rules.

Documentation improvements:

• Added descriptive docstrings to all pytest fixtures in the following test files: test_get_api_token.py, test_capture_reservation_cancel.py, test_get_categories.py, test_get_by_code.py, test_get_gateways.py, test_get_issuers_by_gateway_code.py, test_get_me.py, test_capture.py, test_create.py, test_get_order.py, test_refund.py, test_refund_by_item.py, test_refund_by_shopping_cart.py, test_update.py, test_get_by_gateway_code.py, test_get_payment_methods.py, test_recurring.py, and test_get_transactions.py. These docstrings clarify the purpose of each fixture for future maintainers. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18]
• Added a docstring to the test_afterpay_response function in test_integration_order_response_afterpay_direct.py to clarify its purpose.

Configuration update:

• Updated the pyproject.toml file by removing "D103" from the ignore list, potentially enabling linting for missing docstrings in public modules.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.23%. Comparing base (a2e6567) to head (6f2cf2f).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #37   +/-   ##
=======================================
  Coverage   90.23%   90.23%           
=======================================
  Files         107      107           
  Lines        2355     2355           
=======================================
  Hits         2125     2125           
  Misses        230      230           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.