fix: publish ChainUndelegate event and ledger sig issue

[j75689]

Description

1. fix: publish ChainUndelegate event
2. fix: ledger sig conversion

Rationale

related to: bnb-chain/bnc-cosmos-sdk#389, bnb-chain/bnc-cosmos-sdk#390

Example

n/a

Changes

Notable changes:

• event

Preflight checks

• build passed (make build)
• tests passed (make test)
• integration tests passed (make integration_test)
• manual transaction test passed (cli invoke)

Already reviewed by

n/a

Related issues

n/a

[j75689]

Will Update go.mod after bnc-cosmos-sdk@v0.26.9 release

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 47.87%. Comparing base (3c72c85) to head (b7eb215).

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1015      +/-   ##
==========================================
+ Coverage   47.85%   47.87%   +0.01%     
==========================================
  Files         127      127              
  Lines       12822    12822              
==========================================
+ Hits         6136     6138       +2     
+ Misses       6252     6249       -3     
- Partials      434      435       +1     

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[colorado392]

Ch