Code coverage visualisation

[JamesDawson]

Currently, a number of actions are being evaluated that can display code coverage results as part of the build summary. We need to decide which one(s) fits our needs and finalise the choice(s).

[MikeEvansLarah]

We appear to be using the following actions to generate a markdown summary and publish the summary as a check run:

• https://github.com/irongut/CodeCoverageSummary
• https://github.com/marketplace/actions/markdown-to-summary

However, the check run is being placed into the wrong workflow group (it appears to just go into whatever the first workflow in the list is). This is a known bug with seemingly no fix on the horizon:
https://github.com/orgs/community/discussions/24616