chore(agent): update directive (2/16)

[hahuja2]

This PR updates the directive to be #if ZEND_MODULE_API_NO >= ZEND_7_0_X_API_NO instead of #ifdef PHP7.

[newrelic-php-agent-bot]

Test Suite	Status	Result
Multiverse	❌	5/8 passing
SOAK	❌	79/85 passing

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.27%. Comparing base (ae34b4f) to head (97e1380).

Additional details and impacted files

@@                    Coverage Diff                     @@
##           remove-obsolete-php5-code    #1070   +/-   ##
==========================================================
  Coverage                      77.27%   77.27%           
==========================================================
  Files                            199      199           
  Lines                          28327    28327           
==========================================================
  Hits                           21890    21890           
  Misses                          6437     6437           

Flag	Coverage Δ
agent-for-php-7.2	77.47% <ø> (ø)
agent-for-php-7.3	77.49% <ø> (ø)
agent-for-php-7.4	77.36% <ø> (ø)
agent-for-php-8.0	76.56% <ø> (ø)
agent-for-php-8.1	76.88% <ø> (ø)
agent-for-php-8.2	76.50% <ø> (ø)
agent-for-php-8.3	76.50% <ø> (ø)
agent-for-php-8.4	76.52% <ø> (ø)

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