Fix exceptions during config update
Fix exceptions during config update

Fix NullPointerException when trying to update a spider option if not
present in the configuration file.
Fix ConversionException when handling the update of CFU option that was
already converted to boolean.

Signed-off-by: thc202 <43af82ef30812a20fbcf38b99a6f72cdd3a89ac1@gmail.com>

gmaran23/zaproxy,meitar/zaproxy,Ali-Razmjoo/zaproxy,kingthorin/zaproxy,psiinon/zaproxy,psiinon/zaproxy,zaproxy/zaproxy,zaproxy/zaproxy,kingthorin/zaproxy,meitar/zaproxy,meitar/zaproxy,thc202/zaproxy,gmaran23/zaproxy,Ali-Razmjoo/zaproxy,zaproxy/zaproxy,kingthorin/zaproxy,kingthorin/zaproxy,gmaran23/zaproxy,Ali-Razmjoo/zaproxy,kingthorin/zaproxy,meitar/zaproxy,gmaran23/zaproxy,Ali-Razmjoo/zaproxy,gmaran23/zaproxy,zaproxy/zaproxy,thc202/zaproxy,Ali-Razmjoo/zaproxy,meitar/zaproxy,thc202/zaproxy,meitar/zaproxy,psiinon/zaproxy,zaproxy/zaproxy,thc202/zaproxy,Ali-Razmjoo/zaproxy,kingthorin/zaproxy,gmaran23/zaproxy,zaproxy/zaproxy,psiinon/zaproxy,kingthorin/zaproxy,meitar/zaproxy,meitar/zaproxy,psiinon/zaproxy,gmaran23/zaproxy,thc202/zaproxy,psiinon/zaproxy,thc202/zaproxy,thc202/zaproxy,zaproxy/zaproxy,psiinon/zaproxy,Ali-Razmjoo/zaproxy