Harness failure popup should ignore UNDETERMINED properties

[celinval]

Requested feature: Only included FAILED properties in the failure pop-up
Use case: Debugging a harness failure
Link to relevant documentation (Rust reference, Nomicon, RFC):

Test case:

    /// The unwind value is too low triggering a unwind failure. This will flip all properties to undetermined.
    #[kani::proof]
    #[kani::unwind(1)]
    fn verify_unwrap() {
        let mut option: Option<&str> = Some("hi");
        for i in 0..2 {
            if i % 2 == 0 {
                option = None;
            }
        }
        option.unwrap();
    }

For this test, the harness failure popup will be quite verbose since it will include all properties that were marked with UNDETERMINED.