[BUG] Retrieve list of Observability objects is flaky

[dblock]

What is the bug?

FAILED  observability/observability.yaml (/home/runner/work/opensearch-api-specification/opensearch-api-specification/tests/default/observability/observability.yaml)
    FAILED  CHAPTERS
        PASSED  Retrieve specific Observability object after creation.
            PASSED  PARAMETERS
                PASSED  object_id
            PASSED  REQUEST BODY
            PASSED  RESPONSE STATUS
            PASSED  RESPONSE PAYLOAD BODY
            PASSED  RESPONSE PAYLOAD SCHEMA
            SKIPPED RESPONSE OUTPUT VALUES
        PASSED  Update specific Observability object.
            PASSED  PARAMETERS
                PASSED  object_id
            PASSED  REQUEST BODY
            PASSED  RESPONSE STATUS
            PASSED  RESPONSE PAYLOAD BODY
            PASSED  RESPONSE PAYLOAD SCHEMA
            SKIPPED RESPONSE OUTPUT VALUES
        PASSED  Retrieve specific Observability object after update.
            PASSED  PARAMETERS
                PASSED  object_id
            PASSED  REQUEST BODY
            PASSED  RESPONSE STATUS
            PASSED  RESPONSE PAYLOAD BODY
            PASSED  RESPONSE PAYLOAD SCHEMA
            SKIPPED RESPONSE OUTPUT VALUES
        FAILED  Retrieve list of Observability objects.
            PASSED  REQUEST BODY
            PASSED  RESPONSE STATUS
            FAILED  RESPONSE PAYLOAD BODY (expected totalHits='0', got '1')
            PASSED  RESPONSE PAYLOAD SCHEMA
            SKIPPED RESPONSE OUTPUT VALUES

How can one reproduce the bug?

https://github.com/opensearch-project/opensearch-api-specification/actions/runs/10356187662/job/28665499770

What is the expected behavior?

Test to be reliable.

What is your host/environment?

2.17 CI/CD

Do you have any additional context?

Introduced in #474 likely.