fix: backend-plugin-module role

Signed-off-by: Jack Palmer <jackpalmer@spotify.com>

packages/backend-app-api/src/alpha/featureDiscoveryServiceFactory.test.ts

@@ -65,7 +65,7 @@ describe('featureDiscoveryServiceFactory', () => {
           name: 'detected-module',
           main: 'index.js',
           backstage: {
-            role: 'backend-module',
+            role: 'backend-plugin-module',
           },
         }),
         'index.js': `

packages/backend-app-api/src/alpha/featureDiscoveryServiceFactory.ts

@@ -28,7 +28,7 @@ import { resolve as resolvePath, dirname } from 'path';
 import fs from 'fs-extra';
 import { BackstagePackageJson } from '@backstage/cli-node';
 
-const LOADED_PACKAGE_ROLES = ['backend-plugin', 'backend-module'];
+const LOADED_PACKAGE_ROLES = ['backend-plugin', 'backend-plugin-module'];
 
 /** @internal */
 async function findClosestPackageDir(