Optimize Esti integration tests

[AliRamberg]

Esti tests can take 30+ min, with Azure ADLS/CosmosDB being the slowest.

Issues:

• COMPOSE_PARALLEL_LIMIT: 1 due to docker-compose race conditions
• Cloud backends add network latency (CosmosDB, ADLS Gen2)
• unified-gc-test has 30 min timeout

Ideas: TestContainers, test sharding, LocalStack/Azurite for mocking

Related: #9076 (Docker Compose concurrent map writes)

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Automation Initiative

[AliRamberg]

Discovery Items

1. Split the esti matrix - Run tests against KV and Blobstores independently to identify performance bottlenecks
2. Investigate mock usage - Discover the current use of mocks in esti tests and determine whether we need to run against real cloud implementations (AWS S3, Azure ADLS/CosmosDB, GCP) or if we can use mocks/local alternatives (LocalStack, Azurite, etc.)

[itaiad200]

We should start with Cloud backends add network latency (CosmosDB, ADLS Gen2)