feat: Added instrumentation support for Express 5 beta

[bizob2828]

Description

This originally started as a research spike to see what broke. It turns out not much so I just PRd support for express 5 beta. We will not officially support it because it hasn't been released as generally available. We will keep tabs on any upcoming beta releases and remove the test stanzas when 5.0.0 is out. I will make sure when this lands to include a secondary changelog item to state this is not officially supported just yet.

Most of the changes are around how child applications are mounted. In v4 they used to be mounted as applications, now they are just mixed in. You can see a difference here:

• express 4 - it would create a lazyrouter which registered query, and expressInit which would pre-define handlers
• express 5 - it now doesn't do this and instead just sets on the default app configuration

Also, the routing has changed a little because it migrated to use router@2.0.0-beta. I had to update some definitions and assertions to handle this. Lastly, express 4 used to bind the query and expressInit middleware as part of the mounted application, this is still done but not as first class middleware so I had to loosen some assertions.

Lastly, I added tests for async handlers and how they are handled if they reject.

How to Test

npm run versioned:internal express
npm run versioned:internal express-esm

Related Issues

Closes #2385

[bizob2828]

express-enrouten has been omitted because it doesn't work with express 5. the package hasn't had updates in 7 years and is marked as archived as well