style(test): use literal header access

e2e/imaging/avatar-endpoint.spec.ts

@@ -81,7 +81,7 @@ test("answers conditional requests with 304", async ({ request }) => {
 		avatarPath({ img_format: "png" }),
 	);
 	expect(first.status()).toBe(200);
-	const etag = first.headers()["etag"];
+	const etag = first.headers().etag;
 	expect(etag).toBeTruthy();
 
 	const second = await getThroughEdge(
@@ -92,7 +92,7 @@ test("answers conditional requests with 304", async ({ request }) => {
 		},
 	);
 	expect(second.status()).toBe(304);
-	expect(second.headers()["etag"]).toBe(etag);
+	expect(second.headers().etag).toBe(etag);
 });
 
 test("serves the rendered avatar behind permissive CORS", async ({
@@ -175,7 +175,7 @@ test("the badge endpoint serves an image and revalidates", async ({
 	expect(first.status()).toBe(200);
 	expect(first.headers()["content-type"]).toContain("image/");
 	expect(first.headers()["access-control-allow-origin"]).toBe("*");
-	const etag = first.headers()["etag"];
+	const etag = first.headers().etag;
 	expect(etag).toBeTruthy();
 
 	const second = await getThroughEdge(request, "/api/imaging/badge?code=ADM", {