fix(cli): Add null checks for validation_error to fix MyPy type errors

Co-Authored-By: AJ Steers <[email protected]>

Author: devin-ai-integration[bot]

airbyte_cdk/cli/airbyte_cdk/_manifest.py

@@ -95,19 +95,22 @@ def validate_manifest(manifest_path: Path) -> None:
             try:
                 validate(migrated_manifest, schema)
                 click.echo(f"❌ Validation failed for {manifest_path}:", err=True)
-                click.echo(f"   {validation_error.message}", err=True)
+                if validation_error:
+                    click.echo(f"   {validation_error.message}", err=True)
                 click.echo(
                     "✅ Issues are fixable via migration. Run 'airbyte-cdk manifest migrate' to fix these issues.",
                     err=True,
                 )
                 sys.exit(2)  # Fixable issues
             except ValidationError:
                 click.echo(f"❌ Validation failed for {manifest_path}:", err=True)
-                click.echo(f"   {validation_error.message}", err=True)
+                if validation_error:
+                    click.echo(f"   {validation_error.message}", err=True)
                 sys.exit(3)  # Non-fixable issues
         else:
             click.echo(f"❌ Validation failed for {manifest_path}:", err=True)
-            click.echo(f"   {validation_error.message}", err=True)
+            if validation_error:
+                click.echo(f"   {validation_error.message}", err=True)
             sys.exit(3)  # Non-fixable issues
 
     except FileNotFoundError: