Add null check before calling project_evaluated (#64)

This PR adds a null check in the evaluate method of the Evaluation class
before calling project_evaluated on the formatter. This ensures that
project_evaluated is only called if there are models to evaluate, thus
skipping the output when no model is found.

#### Changes Made
Added a null check in the evaluate method of the Evaluation class.

CHANGELOG.md

@@ -8,6 +8,9 @@ and this project adheres to
 
 ## [Unreleased]
 
+- Add null check before calling `project_evaluated` in the `evaluate` method to
+  prevent errors when no models are found. See PR #64.
+
 ## [0.3.0] - 2024-06-20
 
 ### Added

src/dbt_score/evaluation.py

@@ -72,4 +72,7 @@ def evaluate(self) -> None:
         self.project_score = self._scorer.score_aggregate_models(
             list(self.scores.values())
         )
-        self._formatter.project_evaluated(self.project_score)
+
+        # Add null check before calling project_evaluated
+        if self._manifest_loader.models:
+            self._formatter.project_evaluated(self.project_score)