Fix implicit null issues for php 8.4

[msievenpiper]

Update previously common "implicit" nullable method inputs that are now depricated in php8.4 and future versions.

These changes maintain php7.4 support for the time being but as versions prior to 8.2 are now EoL support for that should be removed at a later stage.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.53%. Comparing base (ccdb744) to head (e1ef866).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main      #40   +/-   ##
=========================================
  Coverage     82.53%   82.53%           
  Complexity      225      225           
=========================================
  Files            49       49           
  Lines           618      618           
=========================================
  Hits            510      510           
  Misses          108      108           

Files with missing lines	Coverage Δ
src/Support/VirtualFile.php	92.31% <100.00%> (ø)

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