Handle target widget type in stacked widget

[hiqua]

Fixes #965.

[hiqua]

I get a

W/System.err: org.isoron.uhabits.core.models.HabitNotFoundException
        at org.isoron.uhabits.widgets.BaseWidgetProvider.getHabitsFromWidgetId(BaseWidgetProvider.kt:115)
        at org.isoron.uhabits.widgets.TargetWidgetProvider.getWidgetFromId(TargetWidgetProvider.kt:25)
        at org.isoron.uhabits.widgets.BaseWidgetProvider.update(BaseWidgetProvider.kt:149)
        at org.isoron.uhabits.widgets.BaseWidgetProvider.onUpdate$lambda-0(BaseWidgetProvider.kt:107)
        at org.isoron.uhabits.widgets.BaseWidgetProvider.lambda$OH7e88rsKqRhrOgJe55zIFJRuuA(BaseWidgetProvider.kt)
        at org.isoron.uhabits.widgets.-$$Lambda$BaseWidgetProvider$OH7e88rsKqRhrOgJe55zIFJRuuA.run(lambda)
        at java.lang.Thread.run(Thread.java:818)

as of 4947ad0 when I create a new widget. Not sure if it's due to my changes, but trying to fix this anyway.

Edit: looks fine as of e06e014, but I'm wondering if there's still something missing with the initialization. Sometimes, restarting the AVD results in the widget not being populated until I open the app. Maybe that's another issue.

[iSoron]

Thanks for tracking this down, @hiqua! Since these changes are for Loop 2.0.3, could you please submit this PR against branch hotfix/2.0.3 instead of dev? There may be a few conflicts because of d0ef749.

[iSoron]

@hiqua Looks good, thanks! I could not reproduce the issue of the widgets being blank after reboot.