dont need rust toolchain twice

.github/workflows/flutter-nightly.yml

@@ -649,14 +649,6 @@ jobs:
           key: ${{ matrix.job.target }}-${{ matrix.job.extra-build-features }}
           cache-directories: "/opt/rust-registry"
 
-      - name: Install Rust toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          target: ${{ matrix.job.target }}
-          override: true
-          profile: minimal # minimal component installation (ie, no documentation)
-
       - name: Install local registry
         run: |
           mkdir -p /opt/rust-registry
@@ -815,14 +807,6 @@ jobs:
           override: true
           profile: minimal # minimal component installation (ie, no documentation)
 
-      - name: Install Rust toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          target: ${{ matrix.job.target }}
-          override: true
-          profile: minimal # minimal component installation (ie, no documentation)
-
       - uses: Swatinem/rust-cache@v2
         with:
           prefix-key: rustdesk-lib-cache