Add request timeout to license URL check (#1700)

Resolves #1689

By default, Playwright limits each test to a 30s runtime. Unfortunately,
when the the test reaches its timeout, it displays an opaque error
message:
<img width="331" alt="Screen Shot 2023-12-05 at 14 42 47"
src="https://github.com/tiny-pilot/tinypilot/assets/6730025/e44424f0-89f3-4569-98b2-7dd3a8dde7ee">

In this case, the test timed out because one of the license URLs took
>30s to respond.

To avoid this issue, I've applied a 10s timeout to each license URL
check.

### Notes
1. I couldn't find a way to catch the actual test's
[TimeoutError](https://playwright.dev/docs/api/class-timeouterror) or
how to set a custom test timeout message 🤷‍♂️
2. I tested this PR via
    * #1701
    * #1702

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e2e/about.spec.js

@@ -107,15 +107,23 @@ test.describe("about dialog", () => {
     const paths = await Promise.all(
       links.map((link) => link.getAttribute("href"))
     );
-    const responses = await Promise.all(
-      paths.map((path) => fetch(`${baseURL}${path}`))
+    const failedUrls = [];
+    await Promise.all(
+      paths
+        .map((path) => `${baseURL}${path}`)
+        .map((url) =>
+          fetch(url, { signal: AbortSignal.timeout(10000) })
+            .then((res) => {
+              if (res.status !== 200) {
+                failedUrls.push(url);
+              }
+            })
+            .catch(() => failedUrls.push(url))
+        )
     );
-    const failedResponses = responses.filter((res) => res.status !== 200);
     expect(
-      failedResponses.length,
-      `License link broken for URLs: ${failedResponses
-        .map((response) => response.url)
-        .join(", ")}`
+      failedUrls.length,
+      `License link broken for URLs: ${failedUrls.join(", ")}`
     ).toBe(0);
   });
 });