Specify launch windowing mode

This CL specifies a launch windowing mode explicitly when launching an
app via intent but desktop-first state is ambiguous.
Currently, the test assumes that when an external display is connected,
the display is in desktop-first mode (i.e., launch an app in freeform);
otherwise, touch-first mode (i.e., launch an app in fullscreen).
But the assumption is not always correct for desktop devices which are
in desktop-first mode by default regardless of the availability of
external displays.
Therefore, we should not assume the default launch windowing mode but
specify it explicitly.

This CL also simplifies the other app launches as well by specifying
launch windowing modes.

Flag: EXEMPT - test fix
Bug: 416610249
Bug: 439950743
Test: WMShellSmokeTestsDesktopMode
Change-Id: Ifbdc414727b900ac5874f742e2966b103b47ab38