Enable execute tool feature flag by default

[nathaliellenaa]

Description

Enable execute tool feature flag by default + update 3.3 release note

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• New functionality includes testing.
• New functionality has been documented.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

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[pyek-bot]

Does this require doc change as well?

[nathaliellenaa]

Does this require doc change as well?

I missed adding doc for this feature during 3.2 release, created the doc PR opensearch-project/documentation-website#11214

[nathaliellenaa]

Local build passed before last rebase

[nathaliellenaa]

Failing test due to throttling

RestMLRAGSearchProcessorIT > testBM25WithBedrockConverseUsingLlmMessages FAILED
    org.opensearch.client.ResponseException: method [POST], host [http://127.0.0.1:43855/], URI [/test/_search?size=5&search_pipeline=pipeline_test], status line [HTTP/1.1 429 Too Many Requests]
    {"error":{"root_cause":[{"type":"remote_connector_throttling_exception","reason":"Error from remote service: The request was denied due to remote server throttling. To change the retry policy and behavior, please update the connector client_config."}],"type":"remote_connector_throttling_exception","reason":"Error from remote service: The request was denied due to remote server throttling. To change the retry policy and behavior, please update the connector client_config."},"status":429}
        at __randomizedtesting.SeedInfo.seed([BF3399337A39DDAE:CD3872492123B0C0]:0)
        at app//org.opensearch.client.RestClient.convertResponse(RestClient.java:501)
        at app//org.opensearch.client.RestClient.performRequest(RestClient.java:384)
        at app//org.opensearch.client.RestClient.performRequest(RestClient.java:359)
        at app//org.opensearch.ml.utils.TestHelper.makeRequest(TestHelper.java:199)
        at app//org.opensearch.ml.utils.TestHelper.makeRequest(TestHelper.java:172)
        at app//org.opensearch.ml.rest.RestMLRAGSearchProcessorIT.performSearch(RestMLRAGSearchProcessorIT.java:1450)
        at app//org.opensearch.ml.rest.RestMLRAGSearchProcessorIT.testBM25WithBedrockConverseUsingLlmMessages(RestMLRAGSearchProcessorIT.java:892)

[dhrubo-os]

Approved and merged in favor of local build.