[Iron] Add topics with zero message counts to the SQLiteStorage::get_metadata(). (backport #1722)

[mergify]

• Closes Ros bag reindex failed to generate topic inside metadata.yaml if the message_count is 0 #1719
• Analog and manual backport of the Add topics with zero message counts to the SQLiteStorage::get_metadata(). #1725.
  Have to do manual backporting because the code base is very different on humble branch in the affected places.

  ---

  This is an automatic backport of pull request [Humble] Add topics with zero message counts to the SQLiteStorage::get_metadata(). #1722 done by Mergify.

[mergify]

Cherry-pick of 5da1796 has failed:

On branch mergify/bp/iron/pr-1722
Your branch is up to date with 'origin/iron'.

You are currently cherry-picking commit 5da1796.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   rosbag2_cpp/test/rosbag2_cpp/test_sequential_reader.cpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   rosbag2_py/test/test_convert.py
	both modified:   rosbag2_storage_sqlite3/src/rosbag2_storage_sqlite3/sqlite_storage.cpp

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[MichaelOrlov]

LGTM with green CI.

[MichaelOrlov]

Pulls: #1766
Gist: https://gist.githubusercontent.com/MichaelOrlov/43423cc3e9fb2097ddc5387b39cfad75/raw/f10196db2dc9d928a62111644e9591441040a80f/ros2.repos
BUILD args: --packages-above-and-dependencies rosbag2_cpp rosbag2_storage_sqlite3 rosbag2_tests
TEST args: --packages-above rosbag2_cpp rosbag2_storage_sqlite3 rosbag2_tests
ROS Distro: iron
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/14400

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