Add allow_nonzero_velocity_at_trajectory_end parameter to exported ros2_controllers config file

[sea-bass]

Description

With the addition of moveit/moveit_resources#198, the YAML equivalence tests in the moveit_setup_controllers package was failing. So this adds that line to the exported configs, which is probably a good default if we want users to use MoveIt Servo easily.

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
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