cli: fix ..<ext> in frontend build output

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/neat-singers-rhyme.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Fixed the file path pattern of many static assets output as part of the frontend build process, where there was an extra `.` before the extension, leading to names like `image-af7946b..png`.

packages/cli/src/lib/bundler/transforms.ts

@@ -154,7 +154,7 @@ export const transforms = (options: TransformOptions): Transforms => {
       ],
       type: 'asset/resource',
       generator: {
-        filename: 'static/[name].[hash:8].[ext]',
+        filename: 'static/[name].[hash:8][ext]',
       },
     },
     {