Express instrumentation handler spans metaissue

[raphael-theriault-swi]

Opening this to more easily keep track of all of the open issues and PRs that relate to and might have context around Express request handler spans not properly tracking async work and not being set as active in the context.

• @opentelemetry/instrumentation-express handler does not run in correct context #2022 is the first issue to describe the problem with spans not being set in the context and has some relevant discussion

• @opentelemetry/instrumentation-express handler does not account for async work #2023 is the first issue to describe how spans are ended prematurely

• Auto instrumentation of express app is not sending exception event in trace #2146 is due to the request handler spans being ended prematurely before any exception can be recorded

• express instrumentation - span end prematurely for non-middleware instrumentations #2442 is a duplicate of @opentelemetry/instrumentation-express handler does not account for async work #2023

• Can't update span name when using OpenTelemetry Express Instrumentation for Node.js #2469 is due to active spans not being set in the context by the instrumentation

• Can't get active span in Express instrumentation. #2617 is also due to active spans not being set in the context by the instrumentation

• feat(express): record exceptions #1657 once had code that addressed the issue but the scope was narrowed to just exceptions

• fix(instrumentation-express): Finish spans after execution #2603 drafts a fix for request handler spans being ended prematurely, but not for the missing active span