Refactor Elasticsearch log formatter to use timezone.from_timestamp

[23tae]

Description

This PR refactors the ElasticsearchJSONFormatter to use the standard Airflow timezone.from_timestamp utility, addressing a TODO in the codebase.
This is a companion PR to #66856, which applies the same refactoring pattern to the Elasticsearch provider.

Key changes

• Task SDK timezone export: Exported from_timestamp in airflow.sdk.timezone to make it part of the public Task SDK API (shared changes with Refactor Opensearch log formatter to use timezone.from_timestamp and export it in Task SDK #66856).
• Compatibility logic: Implemented version-based compatibility logic in the Elasticsearch provider. The formatter now uses the new timezone.from_timestamp on Airflow 3.3.0+ and maintains backward compatibility by falling back to the original pendulum/datetime logic on older Airflow 3.x releases.

Verification Results

I have verified the changes using both prek (ruff) and breeze (standardized Docker environment).

• Unit Tests (Breeze): Passed
• Static Checks (Prek): Passed

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Was generative AI tooling used to co-author this PR?

• Yes

Generated-by: Antigravity following the guidelines

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