Add unit tests covering Salesforce operator field changes

[iamEAP]

What / Why

Although not necessary to exercise every operator in tests (this should be covered by run-crank/typescript-cog-utilities#5), we should at least cover a few new branches of code and ensure the field is set correctly

Scope / UAT Target

• Add operator field assertion in "expected step fields" test (expected key, is optional) for the following objects:
  • Lead
  • Contact
  • Account
  • Opportunity
  • Campaign Member
• Add error outcome assertion when util.compare throws UnknownOperatorError for the following objects:
  • Lead
  • Contact
  • Account
  • Opportunity
  • Campaign Member
• Add error outcome assertion when util.compare throws InvalidOperandError for the following objects:
  • Lead
  • Contact
  • Account
  • Opportunity
  • Campaign Member