Update ufbt_build.yaml

.github/workflows/ufbt_build.yaml

@@ -18,11 +18,6 @@ jobs:
             sdk-channel: dev
           - name: release channel
             sdk-channel: release
-          - name: Unofficial firmware
-            # example URL, replace with a valid one
-            # you can also use other modes for specifying SDK sources
-            sdk-index-url: https://flipper.example.com/directory.json
-            sdk-channel: dev
     name: 'ufbt: Build for ${{ matrix.name }}'
     steps:
       - name: Checkout