Add error message when password is missing

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: JohT

domains/external-dependencies/externalDependencyCharts.py

@@ -108,9 +108,18 @@ def parse_parameters() -> Parameters:
 
 
 def connect_to_graph_database() -> Driver:
+    password = os.environ.get("NEO4J_INITIAL_PASSWORD")
+    if not password:
+        print(
+            f"{SCRIPT_NAME}: Environment variable NEO4J_INITIAL_PASSWORD must be set and non-empty "
+            "before connecting to Neo4j.",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
     graph_driver = GraphDatabase.driver(
         uri="bolt://localhost:7687",
-        auth=("neo4j", os.environ.get("NEO4J_INITIAL_PASSWORD", "")),
+        auth=("neo4j", password),
     )
     graph_driver.verify_connectivity()
     print(f"{SCRIPT_NAME}: Successfully connected to Neo4j")