cmd/tailscale/cli: skip new tab on web login

It doesn't work properly.

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>

cmd/tailscale/cli/web.html

@@ -89,8 +89,7 @@
 	<a href="#" class="mb-4 link font-medium js-loginButton" target="_blank">Reauthenticate</a>
 	{{ end }}
 </main>
-	<script>
-		(function () {
+<script>(function () {
 let loginButtons = document.querySelectorAll(".js-loginButton");
 let fetchingUrl = false;
 
@@ -112,8 +111,6 @@
 	nextUrl.search = nextParams.toString()
 	const url = nextUrl.toString();
 
-				const tab = window.open("/redirect", "_blank");
-
 	fetch(url, {
 		method: "POST",
 		headers: {
@@ -128,14 +125,11 @@
 		}
 		const url = res["url"];
 		if (url) {
-						authUrl = url;
-						tab.location = url;
-						tab.focus();
+			document.location.href = url;
 		} else {
 			location.reload();
 		}
 	}).catch(err => {
-					tab.close();
 		alert("Failed to log in: " + err.message);
 	});
 }
@@ -143,8 +137,7 @@
 Array.from(loginButtons).forEach(el => {
 	el.addEventListener("click", handleClick);
 })
-		})();
-	</script>
+})();</script>
 </body>
 
 </html>