Added test to cover scenario where there is a single ENTRY span in a trace

[avinashkolluru]

Description

Added a test case for TraceStatsEnricher to cover a specific scenario

Checklist:

• My changes generate no new warnings

[codecov]

Codecov Report

Merging #296 (234516a) into main (168e6fe) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main     #296   +/-   ##
=========================================
  Coverage     79.58%   79.58%           
  Complexity     1286     1286           
=========================================
  Files           116      116           
  Lines          5128     5128           
  Branches        465      465           
=========================================
  Hits           4081     4081           
  Misses          836      836           
  Partials        211      211           

Flag	Coverage Δ
unit	79.58% <ø> (ø)

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[github-actions]

Unit Test Results

  75 files  ±0    75 suites  ±0   1m 10s ⏱️ -4s
394 tests +1  394 ✔️ +1  0 💤 ±0  0 ❌ ±0 

Results for commit 7ee3a8e. ± Comparison against base commit 168e6fe.