Fix HVDC Lossless model bug in Copperplate network

[rodrigomha]

Closes #1227

[jd-lara]

Why are we doing this? If its copper plate it should be no-opt

[rodrigomha]

But we model HVDC lines in different subnetworks right? Copperplate balance for each subnetwork using the ref buses, so we want to model HVDC lines between different subnetworks.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.50%. Comparing base (2c1cb5c) to head (64ecc31).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1241      +/-   ##
==========================================
- Coverage   77.57%   77.50%   -0.07%     
==========================================
  Files         124      124              
  Lines       13817    13840      +23     
==========================================
+ Hits        10718    10727       +9     
- Misses       3099     3113      +14     

Flag	Coverage Δ
unittests	77.50% <100.00%> (-0.07%)	⬇️

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

Files with missing lines	Coverage Δ
src/devices_models/devices/AC_branches.jl	61.66% <100.00%> (+0.10%)	⬆️
...c/devices_models/devices/TwoTerminalDC_branches.jl	51.64% <100.00%> (+4.23%)	⬆️

... and 4 files with indirect coverage changes

[github-actions]

Performance Results

Version	Precompile Time
Main	5.996574186
This Branch	5.842004951

Version	Build Time
Main-Build Time Precompile	70.757856482
Main-Build Time Postcompile	0.834743808
This Branch-Build Time Precompile	66.701256524
This Branch-Build Time Postcompile	0.84428455

Version	Solve Time
Main-Solve Time Precompile	582.791871974
Main-Solve Time Postcompile	538.307724861
This Branch-Solve Time Precompile	446.007512348
This Branch-Solve Time Postcompile	405.972298247