Panic when calling Monitor::all() while plugging in external display on macOS

[tpatterson]

To duplicate the problem: Start this test, then once it is going plug in an external monitor. You might have to try it several times before the error happens.

    #[test]
    fn test_xcap_monitor_all() {
        for _ in 0..1000 {
            match Monitor::all() {
                Ok(_) => (),
                Err(e) => core::panic!("Error occurred: {:?}", e),
            }
            // Sleep for a short duration to not overwhelm the system
            sleep(Duration::from_millis(100));
        }
    }

Here is the error:

Error occurred: Error("Get display mode failed")
thread 'interface::screen_detector::tests::test_xcap_monitor_all' panicked at src/interface/screen_detector.rs:390:27:
Error occurred: Error("Get display mode failed")
stack backtrace:
   0: rust_begin_unwind
             at /rustc/7cf61ebde7b22796c69757901dd346d0fe70bd97/library/std/src/panicking.rs:647:5
   1: core::panicking::panic_fmt
             at /rustc/7cf61ebde7b22796c69757901dd346d0fe70bd97/library/core/src/panicking.rs:72:14
   2: ea_client_lib::interface::screen_detector::tests::test_xcap_monitor_all
             at ./src/interface/screen_detector.rs:390:27
   3: ea_client_lib::interface::screen_detector::tests::test_xcap_monitor_all::{{closure}}
             at ./src/interface/screen_detector.rs:386:31
   4: core::ops::function::FnOnce::call_once
             at /rustc/7cf61ebde7b22796c69757901dd346d0fe70bd97/library/core/src/ops/function.rs:250:5
   5: core::ops::function::FnOnce::call_once
             at /rustc/7cf61ebde7b22796c69757901dd346d0fe70bd97/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[nashaofu]

This problem should have been resolved #119

[tpatterson]

Looks great, thank you!