Add airflowctl tasks logs command for retrieving task instance logs

[BobSong-dev]

Summary
Add the airflowctl tasks logs command to fetch a task instance's logs for a given try through the existing REST endpoint.

Changes

• Add TaskInstancesOperations.logs() calling GET /api/v2/dags/{dag_id}/dagRuns/{dag_run_id}/taskInstances/{task_id}/logs/{try_number}.
• Register the tasks logs command: airflowctl tasks logs DAG_ID DAG_RUN_ID TASK_ID [--map-index N] [--try-number N]; --try-number defaults to the latest attempt, matching the webserver UI.
• Keep required parameters positional per the airflowctl parameter style consensus (airflowctl: make required CLI params positional, keep optional as --flag #66768); the issue's suggested --dag-id/--dag-run-id/--task-id flag form was dropped to comply with that convention.
• Limit scope to the primary logs endpoint; externalLogUrl handling is left for a follow-up.

Testing
Added unit tests covering the command: default latest attempt, explicit try number and map index, structured and plain-text log output, 404 handling, and non-404 error propagation. All 35 tests in test_task_command.py pass. Added tasks logs lines to the integration test command list. ruff format and ruff check pass on all changed files.

closes: #69947

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

• Yes — DeepSeek V4 Pro

Generated-by: DeepSeek V4 Pro following the guidelines，I also conducted local testing, and no issues were found.

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