Investigate potential memory leak

[xenowits]

🎯 Problem to be solved

One node in one of our clusters (Obol Mainnet #1/careful-rocket) is experiencing high memory usage.

We need to investigate into this.

🛠️ Proposed solution

This may be caused by a potential memory leak. Use pprof files to visualize points of high memory usage.

🧪 Tests

• Tested by new automated unit/integration/smoke tests
• Manually tested on core team/canary/test clusters
• Manually tested on local compose simnet

[gsora]

It was due to Teku using the new POST method for the get_validator endpoint.

Was fixed already in main, will be fixed for public release on version v0.19.1.