clearRules method
Clears all rules except wheelchair when PRM is on, then recalculates.
Implementation
void clearRules() {
if (_isPrmEnabled) {
_selectedRuleNames
..clear()
..add("wheelchair");
} else {
_selectedRuleNames.clear();
}
_pendingRuleNames.clear();
_isRulesPanelExpanded = false;
_recalculateItinerary();
}