Skip desktop mode LPM if desktop mode isn't on

The difference between RESULT_CONTINUE and RESULT_SKIP is the former
will let the result be carried over to the next LPM, so without copying
over the input launch params, the result of previous LPM and the
previous record is lost.

Bug: 339093954
Test: Last records are preserved when desktop mode is disabled.
Test: atest DesktopModeLaunchParamsModifierTests
Change-Id: Id0af1e0ba037f1c14e10bf97189e8508da166b19