Support relative includes for IDL in local message definition

[hunter-allen-apexai]

Description

This MR fixes relative includes for IDL format. If the user has an IDL file that is in the same directory
as the parent message, and the parent message is being recorded, rosbag2 will crash without reporting
an error. This is avoided by adding a new namespace_hint parameter, modifying the regex used to search
for includes, and applying that information when there is no package nor namespace provided for dependency
collection.

Is this user-facing behavior change?

No.

Did you use Generative AI?

No.

Additional Information

n/a

[MichaelOrlov]

@hunter-allen-apexai Thank you for the PR.

Can you please address test failure in the
https://build.ros2.org/job/Rpr__rosbag2__ubuntu_noble_amd64/910/testReport/junit/rosbag2_cpp/test_local_message_definition_source/can_find_relative_idl_deps/

And linter warning

Error: DEBUG: Using '--root=/__w/rosbag2/rosbag2/rosbag2_cpp/src' argument
Error: /__w/rosbag2/rosbag2/rosbag2_cpp/src/rosbag2_cpp/message_definitions/local_message_definition_source.cpp:139: Lines should be <= 100 characters long [whitespace/line_length] [2]