Add the list of flags in dumpsys

For flags outside of the DesktopExperienceFlags enum, it will only see
those defined in the System UI / WM Shell process.

Command to get it:

$ adb shell dumpsys activity service SystemUIService WMShell

And search for `DesktopExperienceFlags`.

Bug: 389092752
Flag: com.android.window.flags.show_desktop_experience_dev_option
Test: Manual
Change-Id: Ia5e5cb15b29d1852352a3bc57b4d6ba8425f0762