refactor: move crosschain flags to core context in zetaclient

[kevinssgh]

Description

1. Update core context with cross-chain flags
2. Added reference to core context in chain clients and signers
3. Referencing cross-chain flags from core context instead of querying the core each time.

Closes: #1832

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

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 48.14815% with 14 lines in your changes are missing coverage. Please review.

Project coverage is 48.69%. Comparing base (1655c34) to head (25e9518).

❗ Current head 25e9518 differs from pull request most recent head 07c8e94. Consider uploading reports for the commit 07c8e94 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1914      +/-   ##
===========================================
+ Coverage    48.43%   48.69%   +0.26%     
===========================================
  Files          235      235              
  Lines        13377    13381       +4     
===========================================
+ Hits          6479     6516      +37     
+ Misses        6456     6423      -33     
  Partials       442      442              

Files	Coverage Δ
zetaclient/core_context/zeta_core_context.go	89.69% <100.00%> (+0.80%)	⬆️
zetaclient/evm/evm_signer.go	48.44% <100.00%> (+0.50%)	⬆️
zetaclient/bitcoin/bitcoin_client.go	16.64% <75.00%> (+3.34%)	⬆️
zetaclient/evm/evm_client.go	14.89% <0.00%> (+0.03%)	⬆️
zetaclient/bitcoin/bitcoin_signer.go	0.00% <0.00%> (ø)
zetaclient/zetabridge/zetacore_bridge.go	0.00% <0.00%> (ø)

[kevinssgh]

There are a few lines not covered in zetabridge and bitcoin signer. These packages are missing many basic unit tests and I will address these in another PR as they need much more work.

[ws4charlie]

looks good