Uncaught HTTP Error causes problems with generated recipes

[robwoolley]

The ament_cmake_gtest recipe failed to be generated which led to me finding this in the logs:

>>>> 2.2%: Successfully generated recipe for package 'ament_cmake_google_benchmark'.
Failed to read package.xml file from url 'https://raw.github.com/ros2-gbp/ament_cmake-release/release/humble/ament_cmake_gtest/1.3.11-1/package.xml': HTTP Error 429: Too Many Requests
Trying to read from legacy-style url 'https://raw.github.com/ros2-gbp/ament_cmake-release/release/ament_cmake_gtest/1.3.11/package.xml' instead

Prior to that there were other examples as well:

DEBUG:rosdistro:- failed (HTTP Error 429: Too Many Requests), trying "https://raw.githubusercontent.com/ros2-gbp/realtime_support-release/release/humble/tlsf_cpp/0.13.0-2/package.xml"
DEBUG:rosdistro:Skipped "github_manifest_provider()": 
DEBUG:rosdistro:Skip non-bitbucket url "https://github.com/ros2-gbp/realtime_support-release.git"
DEBUG:rosdistro:Skipped "bitbucket_manifest_provider()": Cannot handle non bitbucket url.
Cloning into '.'...
Note: switching to '2cc70b113e45e90cfafd2f8d0513cadaf8c378bb'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

Ways to resolve this could include:

• Propogating the error upwards to cause the action itself to fail
• Adding a pause and then retrying the HTTP request
• Adding credentials to encourage GitHub to allow the requests to continue

Steps to reproduce:

• This only happened for the 3rd combination (master+humble, after master+rolling, and master+jazzy succeeded). One workaround might also be to stagger the GitHub Actions so that it doesn't overwhelm GitHub.