win, build: fix building addons on Windows

Building addons would fail because addon-verify.js dependencies from
tools\doc where not installed. This fixes this issue by installing
those dependencies if addons are to be built.

Fixes: #25096

PR-URL: #25108
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

vcbuild.bat

@@ -449,8 +449,8 @@ if errorlevel 1 goto exit
 
 
 :install-doctools
-REM only install if building doc OR testing doctool
-if not defined doc (
+REM only install if building doc OR testing doctool OR building addons
+if not defined doc if not defined build_addons (
   echo.%test_args% | findstr doctool 1>nul
   if errorlevel 1 goto :skip-install-doctools
 )