refactor: remove duplicate ValidateChainParams function

[skosito]

Description

Removing duplicate ValidateChainParams function in zetaclient and using one from observer types, so it is not maintained on 2 places.

Closes: #1838

Type of change

Cleanup

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Include instructions and any relevant details so others can reproduce.

• Tested CCTX in localnet
• Tested in development environment
• Go unit tests
• Go integration tests
• Tested via GitHub Actions

Checklist:

• I have added unit tests that prove my fix feature works

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 49.88%. Comparing base (ae205b5) to head (0f4aa76).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1863   +/-   ##
========================================
  Coverage    49.88%   49.88%           
========================================
  Files          219      219           
  Lines        12712    12712           
========================================
  Hits          6342     6342           
  Misses        5928     5928           
  Partials       442      442           

Files	Coverage Δ
zetaclient/zetabridge/zetacore_bridge.go	0.00% <0.00%> (ø)

[lumtis]

@skosito renamed FYI, this is a refactor, not a chore. Chore shouldn't not touch the codebase