Isolate telemetry test mock endpoints

[sdairs]

Summary

• give every telemetry test sandbox a unique ingest path instead of sharing /v1/telemetry
• filter received requests by that test-owned path so a delayed child hitting a reused port cannot satisfy or fail another test
• apply the same path isolation to the slow-endpoint case and add focused coverage for stale unmatched requests

Closes #525

Verification

• cargo fmt --all -- --check
• cargo test -p clickhousectl --test telemetry_test
• telemetry test binary repeated 50 times (1,150 tests passed)
• cargo test -p clickhousectl
• cargo clippy -p clickhousectl --all-targets -- -D warnings

Stack

• Position: child 33 of 33 in gh-stack #524
• Base: Require an explicit Cloud integration decision #481 (issue-410-cloud-integration-decision)
• Parent PR is unchanged and should merge first.

[iskakaushik]

LGTM