fix: Use correct constructor for ApiException in PSR-18 PHP library

[phknot]

The PSR-18 version of the api.mustache template uses the wrong constructor for ApiException in two places. It uses the constructor of the normal PHP generated (non-PSR18).

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Mentions:

• @jebentier
• @dkarlovi
• @mandrean
• @jfastnacht
• @ybelenko
• @renepardon

[wing328]

thanks for the pr

please follow step 3 to update the samples

[wing328]

i'll update the pr after mering this pr

thanks for your contribution