rust: remove unnecessary nested unsafe

[catenacyber]

Link to ticket: https://redmine.openinfosecfoundation.org/issues/
None, found by cargo audit job

Describe changes:

• rust: remove recently introduced unnecessary nested unsafe

@jasonish should I let you change CI to check it per PR ?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.48%. Comparing base (49ecf37) to head (d45b5c8).

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #11313   +/-   ##
=======================================
  Coverage   82.47%   82.48%           
=======================================
  Files         934      934           
  Lines      252270   252239   -31     
=======================================
- Hits       208055   208048    -7     
+ Misses      44215    44191   -24     

Flag	Coverage Δ
fuzzcorpus	60.25% <100.00%> (-0.01%)	⬇️
livemode	18.74% <100.00%> (-0.02%)	⬇️
pcap	43.74% <100.00%> (-0.04%)	⬇️
suricata-verify	61.29% <100.00%> (-0.03%)	⬇️
unittests	59.92% <100.00%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

[suricata-qa]

Information: QA ran without warnings.

Pipeline 21107

[jasonish]

@jasonish should I let you change CI to check it per PR ?

Yes, I'll take a look at that.

[victorjulien]

Merged in #11320, thanks!