don't crash if can't find an app in a custom report config
don't crash if can't find an app in a custom report config

not sure exactly what causes this, ran into it locally

SEL-Columbia/commcare-hq,puttarajubr/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,puttarajubr/commcare-hq,qedsoftware/commcare-hq,qedsoftware/commcare-hq,SEL-Columbia/commcare-hq,SEL-Columbia/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,puttarajubr/commcare-hq