fix(otlp-transformer): do not throw when deserializing empty JSON response

[pichlermarc]

Which problem is this PR solving?

When receiving an empty response form the server, the de-serialization code would throw, which caused a log message to be written. This PR changes it so that empty responses from the server are treated as such.

Fixes #5548

Type of change

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

How Has This Been Tested?

• Added Unit tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.95%. Comparing base (4f9b31b) to head (a5f97fc).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5551   +/-   ##
=======================================
  Coverage   94.95%   94.95%           
=======================================
  Files         309      309           
  Lines        7946     7952    +6     
  Branches     1608     1611    +3     
=======================================
+ Hits         7545     7551    +6     
  Misses        401      401           

Files with missing lines	Coverage Δ
...al/packages/otlp-transformer/src/logs/json/logs.ts	100.00% <100.00%> (ø)
...kages/otlp-transformer/src/metrics/json/metrics.ts	100.00% <100.00%> (ø)
.../packages/otlp-transformer/src/trace/json/trace.ts	100.00% <100.00%> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[pichlermarc]

Actually I'm not sure if an empty response is a valid OTLP response or not. It might now be a spec compliant response after all since technically an empty string is not valid JSON.

Related spec: https://opentelemetry.io/docs/specs/otlp/#full-success-1