fix(php-nextgen): do not call static methods dynamically

[simPod]

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[wing328]

thanks for the pr

cc @jebentier (2017/07), @dkarlovi (2017/07), @mandrean (2017/08), @jfastnacht (2017/09), @ybelenko (2018/07), @renepardon (2018/12)

cc @JulianVennen as well @jebentier (2017/07), @dkarlovi (2017/07), @mandrean (2017/08), @jfastnacht (2017/09), @ybelenko (2018/07), @renepardon (2018/12)

[wing328]

the refactor looks good to me

thanks for the contribution

[wing328]

@simPod when you've time, can you please PM me via Slack?

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