[BUG] OpenSearch-Dashboards is slow to initialize as cookie sizes grow

[Morpheus-zzy]

Describe the bug

Use jwt authentication.
OpenSearch-Dashboards initialization is very slow when the cookie size increases.

To Reproduce
Steps to reproduce the behavior:

1. Open OpenSearch-Dashboards
2. Go to the browser DevTools
3. Add cookies for OpenSearch-Dashboards in DevTools
4. Refreshing the page, OpenSearch-Dashboards started very slowly

Expected behavior
The speed of initialization is not affected by the cookie size.
Initialization can be done quickly.

OpenSearch Version
2.18.0

Dashboards Version
2.18.0

Plugins

analysis-nori 2.18.0
opensearch-alerting 2.18.0.0
opensearch-anomaly-detection 2.18.0.0
opensearch-asynchronous-search 2.18.0.0
opensearch-cross-cluster-replication 2.18.0.0
opensearch-custom-codecs 2.18.0.0
opensearch-flow-framework 2.18.0.0
opensearch-geospatial 2.18.0.0
opensearch-index-management 2.18.0.0
opensearch-job-scheduler 2.18.0.0
opensearch-knn 2.18.0.0
opensearch-ml 2.18.0.0
opensearch-neural-search 2.18.0.0
opensearch-notifications 2.18.0.0
opensearch-notifications-core 2.18.0.0
opensearch-observability 2.18.0.0
opensearch-performance-analyzer 2.18.0.0
opensearch-reports-scheduler 2.18.0.0
opensearch-security 2.18.0.0
opensearch-security-analytics 2.18.0.0
opensearch-skills 2.18.0.0
opensearch-sql 2.18.0.0
opensearch-system-templates 2.18.0.0
prometheus-exporter 2.18.0.0
query-insights 2.18.0.0

Screenshots

• Add test cookies
  

• Refreshing the page, /api/core/capabilities requests are extremely slow
  

Host/Environment (please complete the following information):

• Browser and version [Chrome 134.0.6998.88]

Additional context

Add any other context about the problem here.

[10000-ki]

same

[dynek]

I guess we're hitting the same issue, when cookies size exceed 4297 bytes the endpoint becomes slow.

edit: so more checks, it looks that the problem is the whole header's size, not only cookies (5002 bytes OK, more = slow)