Refactor test cases for improved readability and consistency

- Updated test functions in various test files to enhance code clarity by formatting long lines and improving indentation.
- Adjusted assertions to use multi-line formatting for better readability.
- Added new test cases for theme settings API to ensure proper functionality.
- Ensured consistent use of line breaks and spacing across test files for uniformity.

tests/e2e/test_equipment.py

@@ -38,11 +38,8 @@ def test_create_equipment_item(page: Page):
     # Verify the new item appears in the table.
     page.select_option("#equipment-scenario-filter", label=scenario_name)
     expect(
-        page.locator("#equipment-table-body tr").filter(
-            has_text=equipment_name
-        )
+        page.locator("#equipment-table-body tr").filter(has_text=equipment_name)
     ).to_be_visible()
 
     # Verify the feedback message.
-    expect(page.locator("#equipment-feedback")
-           ).to_have_text("Equipment saved.")
+    expect(page.locator("#equipment-feedback")).to_have_text("Equipment saved.")