Use rmw_namespace_validation_result_string() in rmw_create_node

[christophebedard]

rmw_namespace_validation_result_string() -- not rmw_node_name_validation_result_string() -- should be called with the validation result from rmw_validate_namespace().

In practice, this meant that the reason given might have been "unknown result code for rmw node name validation" given that rmw_node_name_validation_result_string() doesn't know about all validation results from rmw_validate_namespace(). However, I believe that we don't test these error messages anywhere and rarely rely on them, so it doesn't/shouldn't affect any tests or functionality.

Related PRs:

• https://github.com/ros2/rmw_fastrtps/pull/765
• https://github.com/ros2/rmw_connextdds/pull/151
• https://github.com/ros2/rmw_zenoh/pull/196

[christophebedard]

CI with the other related rmw implementation PRs except for rmw_zenoh:

• Linux
• Linux-aarch64 (excludes rmw_connextdds_common)
• Linux-rhel
• Windows

[christophebedard]

The ros2action.ros2action.test.test_cli.test_cli test failure looks unrelated.

[clalancette]

The ros2action.ros2action.test.test_cli.test_cli test failure looks unrelated.

I agree, though I will say that I couldn't find a similar failure in the nightly jobs. Regardless, I'm going to go ahead and merge this set of PRs in, and we'll keep an eye on it.