fix: Homepage no longer downloaded on script

[notPlancha]

Currently checkver.ps1 GETs the homepage, even if script is specified, and does nothing with it. This becomes an issue when the homepage doesn't return a 2xx, like a timeout, or a 403 Forbiden (like cloudflare does). I don't see any reason this is the case, so I wrapped this logic in an if/else. I am not sure if this is the best option, or if this is breaking at all (I don't think it is but I'm not completly sure)

fixes #5704.

PS: I'm not sure if I'm supposed to create the PR to the master branch or the develop branch (CONTRIBUTING.md) isn't really clear on that. Right now they're synced so it shouldn't be an issue.