validate if db env values exist in .env (#644)

# Purpose
Completed TODO in config.py

# New Changes
- added validation to pulling .env values to ensure that they exist in
the .env file

# Testing
Explain tests that you ran to verify code functionality.
- [x] I have unit-tested this PR. Otherwise, explain why it cannot be
unit-tested.

see screenshot below

- [x] I have included screenshots of the tests performed below.

<img width="908" height="165" alt="Screenshot 2025-11-25 at 3 12 06 PM"
src="https://github.com/user-attachments/assets/ca81a027-af42-44b2-a619-45989bc7136a"
/>

Author: Syzygicality

gs/backend/config/config.py

@@ -22,12 +22,27 @@ def __init__(self) -> None:
 
 backend_config = BackendConfiguration()
 
-# TODO: Make these throw an exception if they are None
-GS_DATABASE_USER = environ.get("GS_DATABASE_USER")
-GS_DATABASE_PASSWORD = environ.get("GS_DATABASE_PASSWORD")
-GS_DATABASE_LOCATION = environ.get("GS_DATABASE_LOCATION")
-GS_DATABASE_PORT = environ.get("GS_DATABASE_PORT")
-GS_DATABASE_NAME = environ.get("GS_DATABASE_NAME")
+
+def getenv(config: str) -> str:
+    """
+    Validates whether or not database env values exist in .env. If not, throws a value error.
+
+    :param config: Variable in .env
+    :type config: str
+    :return: Value of variable in .env
+    :rtype: str
+    """
+    value = environ.get(config)
+    if not value:
+        raise ValueError(f"{config} is missing from .env.")
+    return value
+
+
+GS_DATABASE_USER = getenv("GS_DATABASE_USER")
+GS_DATABASE_PASSWORD = getenv("GS_DATABASE_PASSWORD")
+GS_DATABASE_LOCATION = getenv("GS_DATABASE_LOCATION")
+GS_DATABASE_PORT = getenv("GS_DATABASE_PORT")
+GS_DATABASE_NAME = getenv("GS_DATABASE_NAME")
 
 DATABASE_CONNECTION_STRING: Final[
     str