ci: [refactor] Move github_import_vs_env to python script

Also, change the yaml anchor name and the step name.
Also, small refactors while touching the files.

.github/workflows/ci.yml

@@ -227,16 +227,9 @@ jobs:
 
       - *CHECKOUT
 
-      - &SET_UP_VS
-        name: Set up VS Developer Prompt
-        shell: pwsh -Command "$PSVersionTable; $PSNativeCommandUseErrorActionPreference = $true; $ErrorActionPreference = 'Stop'; & '{0}'"
-        run: |
-          $vswherePath = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
-          $installationPath = & $vswherePath -latest -property installationPath
-          & "${env:COMSPEC}" /s /c "`"$installationPath\Common7\Tools\vsdevcmd.bat`" -arch=x64 -no_logo && set" | foreach-object {
-            $name, $value = $_ -split '=', 2
-            echo "$name=$value" >> $env:GITHUB_ENV
-          }
+      - &IMPORT_VS_ENV
+        name: Import Visual Studio env vars
+        run: py -3 .github/ci-windows.py "standard" github_import_vs_env
 
       - name: Get tool information
         shell: pwsh
@@ -418,7 +411,7 @@ jobs:
       - name: Run bitcoind.exe
         run: py -3 .github/ci-windows-cross.py print_version
 
-      - *SET_UP_VS
+      - *IMPORT_VS_ENV
 
       - name: Check executable manifests
         run: py -3 .github/ci-windows-cross.py check_manifests