refactor(otlp-exporter-base): don't create blob before sending xhr

[pichlermarc]

Which problem is this PR solving?

Skips creating a blob and passes the Uint8Array directly to request.send(), as it was done before 0.53.0. Both are an acceptable input according to https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/send#parameters, but creating Blobs does not seem to work in React Native.

Fixes #5178

Type of change

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

How Has This Been Tested?

• Manually tested with example from Add a React Native example app to the demo opentelemetry-demo#1781
• Manually tested with example from examples/opentelemetry-web (passing empty headers to force XHR instead of sendBeacon)
• Adapted unit tests
• Existing unit tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.58%. Comparing base (ef80821) to head (3ec05b0).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5193      +/-   ##
==========================================
- Coverage   94.59%   94.58%   -0.02%     
==========================================
  Files         314      314              
  Lines        7993     7993              
  Branches     1611     1611              
==========================================
- Hits         7561     7560       -1     
- Misses        432      433       +1     

see 1 file with indirect coverage changes

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests
• JS Bundle Analysis - Avoid shipping oversized bundles

[pichlermarc]

note: this is the only thing that really changed here, since we're not passing a Blob this test needed to be adapted.

[pichlermarc]

note: I wrapped this in a try/catch to ensure done is called - otherwise if the tests fails it will just say that the test timed out.