fix(otlp-exporter-base): use dynamic import instead of require in esm/esnext build

[pichlermarc]

Which problem is this PR solving?

When bundling with rollup, the compiled files from the ESM build are used. When the bundle is run, require is not defined because it's ESM - also the file it tries to require is not there since it's a bundle now.

This is the case because we have a workaround in the HttpExporterTransport to lazy load a file that requires http until we actually export. We need this workaround to ensure that the @opentelemetry/instrumentation-http package can properly wrap everything - I'm not sure exactly how much of that is actually needed so I'll follow up with some more investigation after we get this fix in.

This PR changes the require() to an await import(), which compiles to

• require() wrapped in a Promise.resolve() for CJS
• import() for esm/esnext

These types of problems are actually prime candidates to test when we start working on

• improv(tests): add e2e test with collector for all of our OTLP exporters #2157
• add bundler tests #4744

While this PR does not add any additional tests, it will unblock bundling with rollup for now. We should, however, get started on #4744 eventually to have this tested in an automated manner.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Manual test using rollup project (we should eventually automate this - see add bundler tests #4744)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.59%. Comparing base (484af40) to head (0199730).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5220      +/-   ##
==========================================
- Coverage   94.60%   94.59%   -0.02%     
==========================================
  Files         315      315              
  Lines        8011     8011              
  Branches     1617     1617              
==========================================
- Hits         7579     7578       -1     
- Misses        432      433       +1     

Files with missing lines	Coverage Δ
...rter-base/src/transport/http-exporter-transport.ts	93.75% <100.00%> (ø)

... and 1 file with indirect coverage changes

[raphael-theriault-swi]

In my experience importing a core module before hooking doesn't actually cause any issues and it gets instrumented fine, we use fs before anything else to load a config file and it's never been a problem.