Open processor "Open in browser" CTAs in a new tab

The home-hero and download-modal "Open in browser" buttons used
window.location.href, which replaced the current tab. Switch to
window.open(..., "_blank", "noopener,noreferrer") to match the
existing EditorStatusCard behaviour.

frontend/editor/src/portal/components/DownloadEditorModal.tsx

@@ -255,7 +255,7 @@ export function DownloadEditorModal({ open, onClose }: Props) {
             variant="secondary"
             leftSection={<OpenInNewRounded sx={{ fontSize: 15 }} />}
             onClick={() => {
-              window.location.href = EDITOR_URL;
+              window.open(EDITOR_URL, "_blank", "noopener,noreferrer");
             }}
           >
             {t("portal.home.download.openInBrowser")}

frontend/editor/src/portal/components/WelcomeBanner.tsx

@@ -78,7 +78,7 @@ export function WelcomeBanner({ footer }: WelcomeBannerProps) {
             className="portal-welcome__cta"
             leftSection={<ExternalLinkIcon size={15} />}
             onClick={() => {
-              window.location.href = EDITOR_URL;
+              window.open(EDITOR_URL, "_blank", "noopener,noreferrer");
             }}
           >
             {t("portal.welcome.openInBrowser")}