fix: use url-parse for url construction (#15670)

This fixes some CodeQL-flagged issues. They're not real issues but the
refactor is small and it'll keep the analysis tools quiet.

site/src/utils/apps.ts

@@ -29,7 +29,12 @@ export const createAppLinkHref = (
 	}
 
 	if (appsHost && app.subdomain && app.subdomain_name) {
-		href = `${protocol}//${appsHost}/`.replace("*", app.subdomain_name);
+		const baseUrl = `${protocol}//${appsHost}`;
+		const url = new URL(baseUrl);
+		url.hostname = appsHost.replace("*", app.subdomain_name);
+		url.pathname = "/";
+
+		href = url.toString();
 	}
 	return href;
 };

site/src/utils/portForward.ts

@@ -12,7 +12,12 @@ export const portForwardURL = (
 	const suffix = protocol === "https" ? "s" : "";
 
 	const subdomain = `${port}${suffix}--${agentName}--${workspaceName}--${username}`;
-	return `${location.protocol}//${host}`.replace("*", subdomain);
+
+	const baseUrl = `${location.protocol}//${host}`;
+	const url = new URL(baseUrl);
+	url.hostname = host.replace("*", subdomain);
+
+	return url.toString();
 };
 
 // openMaybePortForwardedURL tries to open the provided URI through the