update: do not launch the downloaded exe in Winstore builds

The API is forbidden.

It could be done with this winrt API:
https://docs.microsoft.com/en-us/windows/uwp/launch-resume/launch-the-default-app-for-a-file
13 jobs for !12 with winrt/10 in 63 minutes and 36 seconds (queued for 2 seconds)
latest detached
Status Job ID Name Coverage
  Build
passed #395090
amd64 docker
android-arm

00:13:12

passed #395091
amd64 docker
android-arm64

00:12:59

passed #395092
amd64 docker
android-x86

00:16:39

passed #395093
amd64 docker
android-x86_64

00:16:44

passed #395084
amd64 docker
debian

00:11:35

passed #395088
macos
ios-arm64

00:39:13

passed #395089
macos
ios-armv7

00:54:07

passed #395087
macos
macos

00:54:58

passed #395086
amd64 docker
raspbian-arm

00:10:06

passed #395085
amd64 docker
snap

00:21:04

passed #395081
amd64 docker
win32

00:41:43

passed #395082
amd64 docker
win64

00:46:02

passed #395083
amd64 docker
win64-llvm

00:20:53