Transform UniFFI SecurityShieldBuilder to value type semantics

[danvleju-rdx]

To improve the handling of TCA state in the iOS host, we need to transform the UniFFI SecurityShieldBuilder to use value type semantics, similar to how the TransactionBuilder is implemented in radix-engine-toolkit.

This change means that every mutating function will return a new instance of SecurityShieldBuilder.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.3%. Comparing base (4870dd8) to head (b663671).

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #312   +/-   ##
=====================================
  Coverage   93.3%   93.3%           
=====================================
  Files       1111    1111           
  Lines      24182   24240   +58     
  Branches      79      79           
=====================================
+ Hits       22570   22628   +58     
  Misses      1597    1597           
  Partials      15      15           

Flag	Coverage Δ
kotlin	97.1% <ø> (ø)
rust	92.8% <100.0%> (+<0.1%)	⬆️
swift	94.8% <100.0%> (-0.1%)	⬇️

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Files with missing lines	Coverage Δ
.../Profile/MFA/SecurityShieldBuilder+Swifified.swift	100.0% <100.0%> (ø)
...mfa/security_structures/security_shield_builder.rs	95.2% <100.0%> (+1.2%)	⬆️