[humble] Install signal handlers in recorder only inside record method (backport #1464)

[mergify]

This is an automatic backport of pull request #1464 done by Mergify.
Cherry-pick of 195e406 has failed:

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	both modified:   rosbag2_py/src/rosbag2_py/_transport.cpp

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[MichaelOrlov]

Gist: https://gist.githubusercontent.com/MichaelOrlov/ffd4e1e650698d81c8655248e5a3d80e/raw/668a0afe60ac3b01e1302181ce22bb734d1bb4fb/ros2.repos
BUILD args: --packages-above-and-dependencies rosbag2_py
TEST args: --packages-above rosbag2_py
ROS Distro: humble
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/13103

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[fujitatomoya]

@MichaelOrlov thanks for resolving the conflicts. lgtm