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.

routes/costs.py

@@ -73,7 +73,8 @@ def create_capex(item: CapexCreate, db: Session = Depends(get_db)):
     if not cid:
         code = (payload.pop("currency_code", "USD") or "USD").strip().upper()
         currency_cls = __import__(
-            "models.currency", fromlist=["Currency"]).Currency
+            "models.currency", fromlist=["Currency"]
+        ).Currency
         currency = db.query(currency_cls).filter_by(code=code).one_or_none()
         if currency is None:
             currency = currency_cls(code=code, name=code, symbol=None)
@@ -100,7 +101,8 @@ def create_opex(item: OpexCreate, db: Session = Depends(get_db)):
     if not cid:
         code = (payload.pop("currency_code", "USD") or "USD").strip().upper()
         currency_cls = __import__(
-            "models.currency", fromlist=["Currency"]).Currency
+            "models.currency", fromlist=["Currency"]
+        ).Currency
         currency = db.query(currency_cls).filter_by(code=code).one_or_none()
         if currency is None:
             currency = currency_cls(code=code, name=code, symbol=None)