scale up Metabase node instance type

[Gyan-Gupta-Rtsl]

Ticket: 503 error when loading metabase BD

Because

1. Metabase pod was getting evicted due to memory pressure on the t3.small node.
2. After the Metabase upgrade, the workload required more memory than the available node capacity.

This addresses

Upgrades the Metabase node instance type from t3.small to t3.medium.

Test Instruction

1. Verify Metabase pod is running without eviction.
2. Access https://metabase.bd.simple.org/ and confirm the dashboard loads successfully.

[demarcqarnaud]

Ok for me.