Add expects: fail and ok

[Kudisoldier]

Summary

Adds two new assertion wrappers to ExpectHelper:

• I.expectFail() to explicitly fail a test with an optional custom message
• I.expectOk() to assert that a value is truthy

Changes

• Implemented expectFail(customErrorMsg = 'expect fail')

• Implemented expectOk(actualValue, customErrorMsg = '')

• Added TypeScript definitions for both methods

• Added README documentation with examples

• Added unit tests covering:

  • custom failure message
  • default failure message
  • truthy values passing
  • falsy values failing with custom/default Chai messages

Testing

Added tests in index_test.js for both new wrappers.

[Kudisoldier]

@thomashohn could you run a workflow and make an review, please?

[Kudisoldier]

@thomashohn Can you also merge this PR, please? cuz i don't have an active merge button in UI

[thomashohn]

@kobenguyent - can you review this one - I can merge it at create an release if it's ok