wrong error message in LinkHandler.kt verifyDownloadLink()

The logic the defines the error message logic is inverted.
If allowlisted is false (= not allowlisted) but https is true it will show the "not using HTTPS" error message
If https is false (= not using https) but allowlisted=true it will show the "not-allowlisted" error message

``` val comment =
if (allowlisted) {
"The download link is from a non-allowlisted URL"
} else if (https) {
"The download link is not using HTTPS"
} else {
"The download link is from a non-allowlisted URL and is not using HTTPS"
}
```