[v0.36.x] Fix --testnet to use https registry

[Geod24]

This currently prevent users from accessing the network.

[codecov[bot]]

Codecov Report

Merging #3157 (67976ea) into v0.36.x (6b0a7e4) will decrease coverage by 60.28%. The diff coverage is n/a.

@@             Coverage Diff              @@
##           v0.36.x    #3157       +/-   ##
============================================
- Coverage    80.03%   19.74%   -60.29%     
============================================
  Files          210       61      -149     
  Lines        18849     2715    -16134     
============================================
- Hits         15085      536    -14549     
+ Misses        3764     2179     -1585     

Flag	Coverage Δ
integration	19.74% <ø> (-6.95%)	:arrow_down:
unittests	?

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

Impacted Files	Coverage Δ
source/scpd/quorum/QuorumTracker.d	0.00% <0.00%> (-100.00%)	:arrow_down:
source/agora/utils/TxBuilder.d	0.00% <0.00%> (-98.58%)	:arrow_down:
source/agora/utils/Utility.d	0.00% <0.00%> (-92.86%)	:arrow_down:
source/agora/utils/Test.d	0.00% <0.00%> (-91.51%)	:arrow_down:
source/agora/utils/SCPPrettyPrinter.d	8.92% <0.00%> (-82.80%)	:arrow_down:
source/scpd/Cpp.d	58.62% <0.00%> (-38.86%)	:arrow_down:
source/agora/utils/PrettyPrinter.d	77.14% <0.00%> (-22.06%)	:arrow_down:
source/scpd/scp/Slot.d	50.00% <0.00%> (-16.67%)	:arrow_down:
source/scpd/types/Stellar_SCP.d	62.18% <0.00%> (-6.81%)	:arrow_down:
source/scpd/scp/SCP.d	100.00% <0.00%> (ø)
... and 149 more

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