Cast Sequence to list on assignment (with templates)

[InvincibleRMC]

Description

With templates

My proposal on what the solution for The Sequence Api discussion.
Zulip discussion here.
Is this user-facing behavior change?

Yes in the past users type would only change on receiving from a subscriber but, now the change is done on assignment to be more inline with numpy.array and array.array casts.
Did you use Generative AI?
Additional Information

[InvincibleRMC]

@christophebedard here is an implementation with straight templates. The only jankness comes not being able to apply indents to templates nicely. If there is some cleaner way I would love to know. Trying to use the empy documentation was trying.

[InvincibleRMC]

Pulls: #249
Gist: https://gist.githubusercontent.com/InvincibleRMC/92aa793f18157212d6b107cf5bb51435/raw/fed5b0c61dd10d8e464ffc8711c11964bb7461ca/ros2.repos
BUILD args: --continue-on-error --packages-above-and-dependencies rosidl_generator_py
TEST args: --packages-above rosidl_generator_py
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/18129

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[InvincibleRMC]

Pulls: #249
Gist: https://gist.githubusercontent.com/InvincibleRMC/eb456bb5d936910bdad666e94a74882c/raw/fed5b0c61dd10d8e464ffc8711c11964bb7461ca/ros2.repos
BUILD args: --continue-on-error --packages-above-and-dependencies rosidl_generator_py
TEST args: --packages-above rosidl_generator_py
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/18136

• Linux
• Linux-aarch64
• Linux-rhel
• Windows