Commands: Print CA cert's SHA256 in tls ping (#5644)

And https://github.com/XTLS/Xray-core/issues/5642#issuecomment-3840806246

---------

Co-authored-by: RPRX <63339210+RPRX@users.noreply.github.com>

common/utils/access_field.go

@@ -0,0 +1,17 @@
+package utils
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+// AccessField can used to access unexported field of a struct
+// valueType must be the exact type of the field or it will panic
+func AccessField[valueType any](obj any, fieldName string) *valueType {
+	field := reflect.ValueOf(obj).Elem().FieldByName(fieldName)
+	if field.Type() != reflect.TypeOf(*new(valueType)) {
+		panic("field type: " + field.Type().String() + ", valueType: " + reflect.TypeOf(*new(valueType)).String())
+	}
+	v := (*valueType)(unsafe.Pointer(field.UnsafeAddr()))
+	return v
+}