fix: Add a test for validation of empty params

lib/services/addon-service.test.js

@@ -362,3 +362,22 @@ test('should reject updating addon config with missing required parameter', asyn
         { instanceOf: ValidationError },
     );
 });
+
+test('Should reject addon config if a required parameter is just the empty string', async t => {
+    const { addonService } = getSetup();
+
+    const config = {
+        provider: 'simple',
+        enabled: true,
+        parameters: {
+            url: '',
+            var: 'some-value',
+        },
+        events: [FEATURE_CREATED],
+    };
+
+    await t.throwsAsync(
+        async () => addonService.createAddon(config, 'me@mail.com'),
+        { instanceOf: ValidationError },
+    );
+});