[v0.39] Remove DKG submission backward-compat logic

[jordanschalm]

Backport of #7096

v0.39.0 includes several backward-compatibility measures to allow one software version to operate both before and after the protocol state upgrade. This PR removes the backward-compatibility logic for DKG result submission (only submit using v2 transaction format).

⚠️ For live networks, this change must be deployed strictly after the Protocol State Upgrade Process. Specifically after both the protocol state upgrade and after the smart contract upgrade.

Deployment to Testnet/Mainnet

We are performing a staged upgrade process to Protocol State v2, with Testnet first and Mainnet next. We will test this change on Testnet following its upgrade, but would like to make it difficult for Mainnet operators to accidentally upgrade prematurely to this version before the Mainnet upgrade is complete.

• Tag an alpha version off this branch, like v0.39.1-unsafe-compat-disabled and build images
  • CI Build
• Following Testnet upgrade, deploy v0.39.1-unsafe-compat-disabled to Testnet
• Following Mainnet upgrade, merge and tag a regular release v0.39.1 and build images
• Deploy v0.39.1 to Mainnet

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.26%. Comparing base (ad1076f) to head (f4129c1).

Additional details and impacted files

@@            Coverage Diff             @@
##            v0.39    #7097      +/-   ##
==========================================
+ Coverage   41.24%   41.26%   +0.01%     
==========================================
  Files        2138     2138              
  Lines      188585   188495      -90     
==========================================
- Hits        77782    77776       -6     
+ Misses     104307   104226      -81     
+ Partials     6496     6493       -3     

Flag	Coverage Δ
unittests	41.26% <ø> (+0.01%)	⬆️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[AlexHentschel]

🧹 ✨

[durkmurder]

🚀