Add support for variadic parameters and null values

[cleptric]

before	after

Adding support for variadic parameters and null values in stacktraces.
Method was called with:

Numbers::process(10, null, 40, 50, 60, 70);

Closes #1645

[poldixd]

Since updating to version 4.13.0, I’m encountering the following error during CI tests:

  Undefined array key 0
  at vendor/sentry/sentry/src/FrameBuilder.php:226
    222▕             if ($reflectionParameter->isVariadic()) {
    223▕                 // For variadic parameters, collect all remaining arguments into an array
    224▕                 $variadicArgs = [];
    225▕                 for ($i = $parameterPosition; $i < \count($backtraceFrameArgs); ++$i) {
  ➜ 226▕                     $variadicArgs[] = $backtraceFrameArgs[$i];
    227▕                 }
    228▕                 $argumentValues[$reflectionParameter->getName()] = $variadicArgs;
    229▕                 // Variadic parameter is always the last one, so we can break
    230▕                 break;
      +15 vendor frames 

Interestingly, I’m unable to reproduce this issue locally.