fix(testing): Handles Apdex metrics count correctly

[mfulb]

The existing code did not handle an Apdex metric correctly if a count of "1" was specified. It only worked if no count was specified. This change allows either form to work.

[newrelic-php-agent-bot]

Test Suite	Status	Result
Multiverse	✅	7/7 passing
SOAK	❌	55/56 passing

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.32%. Comparing base (819a76d) to head (b012663).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev     #957   +/-   ##
=======================================
  Coverage   78.32%   78.32%           
=======================================
  Files         194      194           
  Lines       26880    26880           
=======================================
  Hits        21055    21055           
  Misses       5825     5825           

Flag	Coverage Δ
agent-for-php-7.2	78.33% <ø> (ø)
agent-for-php-7.3	78.35% <ø> (ø)
agent-for-php-7.4	78.06% <ø> (ø)
agent-for-php-8.0	78.08% <ø> (ø)
agent-for-php-8.1	78.07% <ø> (ø)
agent-for-php-8.2	77.67% <ø> (ø)
agent-for-php-8.3	77.67% <ø> (ø)

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