Allow setting undefined windowing mode

[Xtr126]

I know you're busy, as you said on Telegram. When you have some free time, please have a look at this and the other PR #184.

In AOSP, there's code to persist task bounds/window size for freeform windowing mode, in desktop mode where apps open in freeform windows by default. However, Smartdock overrides this by forcibly setting its own task bounds, causing the app window size to reset every time the app is launched. This PR makes it set the launch mode to WINDOWING_MODE_UNDEFINED when the user selects "Undefined", allowing AOSP to manage the windowing mode and task bounds for the app on it's own.

Here's the link for the task bounds code if you're interested:
https://android.googlesource.com/platform/frameworks/base/+/e6eaac80a6d4809bc94d1482a7cc23eb0288683d/services/core/java/com/android/server/wm/Task.java#1978

[axel358]

@Xtr126 Rather than adding another launch mode. Maybe we could make the default launch mode behave as undefined through an option instead?

[Xtr126]

@Xtr126 Rather than adding another launch mode. Maybe we could make the default launch mode behave as undefined through an option instead?

Yeah, I can also see how that would result in a cleaner UI. Like add a checkbox to override launch mode.