fix: Assorted Permissioned Domain fixes

[mvadari]

High Level Overview of Change

Removed unnecessary check for slePd initialization (std::make_shared cannot return a nullptr).

Context of Change

AI code review

API Impact

N/A

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.5%. Comparing base (0eedefb) to head (df8c386).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #6587   +/-   ##
=======================================
  Coverage     81.4%   81.5%           
=======================================
  Files          997     997           
  Lines        74410   74409    -1     
  Branches      7562    7553    -9     
=======================================
+ Hits         60598   60613   +15     
+ Misses       13812   13796   -16     

Files with missing lines	Coverage Δ
...tors/permissioned_domain/PermissionedDomainSet.cpp	100.0% <ø> (ø)

... and 7 files with indirect coverage changes

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