Explicitly close log file descriptor in the supervise function

[adilkhash]

---

Airflow doesn't close log file descriptor properly hence leading to too many open files error from the operating system.

closes: #51624

[adilkhash]

@kaxil hi, do I need to write tests here? (looks like as a non-trivial case)

[kaxil]

Yeah but Mypy is failing though:

task-sdk/src/airflow/sdk/execution_time/supervisor.py:1580: error: Incompatible
types in assignment (expression has type "TextIOWrapper", variable has type
"Optional[BufferedWriter]")  [assignment]
                log_file_descriptor = log_file.open("a", buffering=1)
                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
task-sdk/src/airflow/sdk/execution_time/supervisor.py:1581: error: Argument 1
to "WriteLogger" has incompatible type "Optional[BufferedWriter]"; expected
"Optional[TextIO]"  [arg-type]
    ...ing_logger: WrappedLogger = structlog.WriteLogger(log_file_descriptor)
                                                         ^~~~~~~~~~~~~~~~~~~
Found 2 errors in 1 file (checked 110 source files)

Error 1 returned

[adilkhash]

@ashb @uranusjr thanks for quick review. failing tests were fixed

[github-actions]

Backport successfully created: v3-0-test

Status	Branch	Result
✅	v3-0-test