Make sky logs with piping handle interrupts gracefully

[concretevitamin]

If using sky logs .. | grep ... in a pipe, then ctrl-c would print out a long stacktrace:

$ sky logs sky-spot-controller-abb92b6d 34 | grep 'preempted from'
(zh-14-26 pid=97928) I 09-13 04:21:03 recovery_strategy.py:355] Cluster is preempted from zone us-west1-a.
(zh-14-26 pid=97928) I 09-13 05:31:15 recovery_strategy.py:355] Cluster is preempted from zone us-west1-b.
^C--- Logging error ---
Traceback (most recent call last):
  File "/opt/conda/lib/python3.9/logging/__init__.py", line 1087, in emit
    self.flush()
BrokenPipeError: [Errno 32] Broken pipe
Call stack:
  File "/home/ubuntu/.local/bin/sky", line 8, in <module>
    sys.exit(cli())
  File "/home/ubuntu/.local/lib/python3.9/site-packages/click/core.py", line 1128, in __call__
    return self.main(*args, **kwargs)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/click/core.py", line 1053, in main
    rv = self.invoke(ctx)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/utils/common_utils.py", line 147, in _record
    return f(*args, **kwargs)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/cli.py", line 776, in invoke
    return super().invoke(ctx)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/ubuntu/.local/lib/python3.9/site-packages/click/core.py", line 1395, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/utils/common_utils.py", line 168, in _record
    return f(*args, **kwargs)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/cli.py", line 1210, in logs
    core.tail_logs(cluster, job_id)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/core.py", line 354, in tail_logs
    backend.tail_logs(handle, job_id)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/backends/cloud_vm_ray_backend.py", line 2403, in tail_logs
    returncode = self.run_on_head(
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/utils/common_utils.py", line 168, in _record
    return f(*args, **kwargs)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/backends/cloud_vm_ray_backend.py", line 2692, in run_on_head
    return runner.run(
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/utils/command_runner.py", line 255, in run
    return log_lib.run_with_log(' '.join(command),
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/skylet/log_lib.py", line 233, in run_with_log
    proc.wait()
  File "/opt/conda/lib/python3.9/subprocess.py", line 1189, in wait
    return self._wait(timeout=timeout)
  File "/opt/conda/lib/python3.9/subprocess.py", line 1917, in _wait
    (pid, sts) = self._try_wait(0)
  File "/opt/conda/lib/python3.9/subprocess.py", line 1875, in _try_wait
    (pid, sts) = os.waitpid(self.pid, wait_flags)
  File "/home/ubuntu/.local/lib/python3.9/site-packages/sky/backends/backend_utils.py", line 1909, in interrupt_handler
    logger.warning(f'{colorama.Fore.LIGHTBLACK_EX}The job will keep '
Message: '\x1b[90mThe job will keep running after Ctrl-C.\x1b[0m'
Arguments: ()
Shared connection to 44.210.146.121 closed.

Aborted!
Exception ignored in: <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'>
BrokenPipeError: [Errno 32] Broken pipe