fix: use require instead of assert to prevent nil dereference panic in CORS test

The test used assert.NoError (non-fatal) for GetBucketCors, then
immediately accessed getResp.CORSRules. When the API returns an error,
getResp is nil causing a panic. Switch to require.NoError/NotNil/Len
so the test stops before dereferencing a nil response.

test/s3/cors/s3_cors_test.go

@@ -140,7 +140,7 @@ func TestCORSConfigurationManagement(t *testing.T) {
 		Bucket:            aws.String(bucketName),
 		CORSConfiguration: corsConfig,
 	})
-	assert.NoError(t, err, "Should be able to put CORS configuration")
+	require.NoError(t, err, "Should be able to put CORS configuration")
 
 	// Wait for metadata subscription to update cache
 	time.Sleep(50 * time.Millisecond)
@@ -149,9 +149,9 @@ func TestCORSConfigurationManagement(t *testing.T) {
 	getResp, err := client.GetBucketCors(context.TODO(), &s3.GetBucketCorsInput{
 		Bucket: aws.String(bucketName),
 	})
-	assert.NoError(t, err, "Should be able to get CORS configuration")
-	assert.NotNil(t, getResp.CORSRules, "CORS configuration should not be nil")
-	assert.Len(t, getResp.CORSRules, 1, "Should have one CORS rule")
+	require.NoError(t, err, "Should be able to get CORS configuration")
+	require.NotNil(t, getResp.CORSRules, "CORS configuration should not be nil")
+	require.Len(t, getResp.CORSRules, 1, "Should have one CORS rule")
 
 	rule := getResp.CORSRules[0]
 	assert.Equal(t, []string{"*"}, rule.AllowedHeaders, "Allowed headers should match")