Fix verifyValidatorsUpdate and mainchain registration logic

[mitsuaki-u]

What was the problem?

This PR resolves #9039 #9041 #8204

How was it solved?

• Update verifyValidatorsUpdate logic to check new active validator bft weights
• Fix mainchain registration bug
• Remove unused utility functions
• Add missing tests

How was it tested?

Updated relevant tests

[codecov]

Codecov Report

Merging #9042 (e6a83d2) into release/6.0.0 (aa95c24) will increase coverage by 0.00%.
Report is 3 commits behind head on release/6.0.0.
The diff coverage is 100.00%.

@@              Coverage Diff               @@
##           release/6.0.0    #9042   +/-   ##
==============================================
  Coverage          83.53%   83.53%           
==============================================
  Files                603      603           
  Lines              22667    22669    +2     
  Branches            3351     3348    -3     
==============================================
+ Hits               18934    18937    +3     
+ Misses              3733     3732    -1     

Files	Coverage Δ
...ommander/src/bootstrapping/commands/keys/create.ts	100.00% <100.00%> (ø)
...rability/base_interoperability_internal_methods.ts	92.93% <100.00%> (+0.32%)	⬆️
...ework/src/modules/interoperability/certificates.ts	100.00% <ø> (ø)
...erability/sidechain/commands/register_mainchain.ts	100.00% <100.00%> (ø)
framework/src/modules/interoperability/utils.ts	89.21% <100.00%> (-1.56%)	⬇️
framework/src/modules/token/cc_method.ts	100.00% <100.00%> (ø)