feat: add an option to IsObject to exclude functions from object checks

[niskyB]

Description

IsObject returned true for functions despite the documented behavior. This PR resolves the issue by introducing an option to exclude functions from object checks.

Checklist

• the pull request title describes what this PR does (not a vague title like Update index.md)
• the pull request targets the default branch of the repository (develop)
• the code follows the established code style of the repository
  • npm run prettier:check passes
  • npm run lint:check passes
• tests are added for the changes I made (if any source code was modified)
• documentation added or updated
• I have run the project locally and verified that there are no errors

Fixes

fixes #2515

[Setitch]

let a = () => {};
console.log(typeof a); // outcome => "function"
console.log(a instanceof Object); // outcome => true

Functions are objects in js therefore isObject should treat functions as objects by JS standard.
However i presume additional option passed to decorator which would allow some control (exclude functions from being treated by the validator as objects) would be much better than going against the language principles.

[niskyB]

Could you please check this again? @Setitch