GHA: drop installing impacket for curl built without SMB support

Ref: #20846

Closes #20868

.github/workflows/windows.yml

@@ -633,7 +633,10 @@ jobs:
       - name: 'install test prereqs'
         if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
         timeout-minutes: 2
-        run: python3 -m pip --disable-pip-version-check --no-input --no-cache-dir install --progress-bar off --prefer-binary -r tests/requirements.txt
+        run: |
+          if "bld/src/curl.exe" --disable -V 2>/dev/null | grep smb; then
+            python3 -m pip --disable-pip-version-check --no-input --no-cache-dir install --progress-bar off --prefer-binary -r tests/requirements.txt
+          fi
 
       - name: 'run tests'
         if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
@@ -851,9 +854,11 @@ jobs:
             image: 'windows-11-arm'
             openssh: 'OpenSSH-Windows'
             tflags: '--min=1650'
+            # disable SMB to save 30-60 seconds by omitting prereqs, to counteract the slower test run step
             config: >-
               -DENABLE_DEBUG=ON
               -DCURL_USE_SCHANNEL=ON
+              -DCURL_DISABLE_SMB=ON
               -DUSE_WIN32_IDN=ON -DENABLE_UNICODE=ON -DUSE_SSLS_EXPORT=ON
 
       fail-fast: false
@@ -1029,7 +1034,7 @@ jobs:
               --location "https://github.com/PowerShell/Win32-OpenSSH/releases/download/${OPENSSH_WINDOWS_VERSION}/OpenSSH-Win64.zip" --output pkg.bin
             sha256sum pkg.bin && sha256sum pkg.bin | grep -qwF -- "${OPENSSH_WINDOWS_SHA256}" && unzip pkg.bin && rm -f pkg.bin
           fi
-          if [ "${MATRIX_IMAGE}" != 'windows-11-arm' ]; then  # save 30-60 seconds, to counteract the slower test run step
+          if "bld/src/${MATRIX_TYPE}/curl.exe" --disable -V 2>/dev/null | grep smb; then
             python3 -m pip --disable-pip-version-check --no-input --no-cache-dir install --progress-bar off --prefer-binary -r tests/requirements.txt
           fi