🐛 Fix hasOwn function implementation to ensure proper property checking

[welkinwong]

In browsers that lack native Object.hasOwn support, assigning Object.prototype.hasOwnProperty.call to a variable (e.g., hasOwn = Object.prototype.hasOwnProperty.call) detaches the call method from its original function context. This results in a runtime error: hasOwn is not a function.

[coveralls]

coverage: 97.465% (-0.03%) from 97.492%
when pulling 0baf4ee on welkinwong:fix-lib-hasown-lagacy
into a0c1f9d on share:master.

[ericyhwang]

Thank you for the fix! We're unsure how the .call got through in the first place.

Coverage shows a drop, but that's fine since it's hard to test the fallback in any remotely recent version of Node.