Change the way invalid ProTxes are handled in `addUnchecked` and `existsProviderTxConflict` (#2691)
Change the way invalid ProTxes are handled in `addUnchecked` and `existsProviderTxConflict` (#2691)

* Invalid ProTxes should never reach addUnchecked

* Invalid ProTxes should not cause existsProviderTxConflict to crash

dashpay/dash,UdjinM6/dash,UdjinM6/dash,biblepay/biblepay,nmarley/dash,ionomy/ion,biblepay/biblepay,biblepay/biblepay,dashpay/dash,nmarley/dash,ionomy/ion,biblepay/biblepay,UdjinM6/dash,ionomy/ion,ionomy/ion,nmarley/dash,dashpay/dash,nmarley/dash,nmarley/dash,biblepay/biblepay,thelazier/dash,ionomy/ion,biblepay/biblepay,biblepay/biblepay,thelazier/dash,dashpay/dash,nmarley/dash,dashpay/dash,ionomy/ion,thelazier/dash,thelazier/dash,UdjinM6/dash,thelazier/dash,biblepay/biblepay,UdjinM6/dash,nmarley/dash