remove customFieldId optional in queryCondition

app/src/main/java/net/pokeranalytics/android/model/filter/QueryCondition.kt

@@ -513,7 +513,7 @@ sealed class QueryCondition : FilterElementRow {
     }
 
     interface CustomFieldRelated {
-        var customFieldId : String?
+        var customFieldId : String
 
         fun customFieldName(realm: Realm): String {
             val query = realm.where(CustomField::class.java)
@@ -532,7 +532,7 @@ sealed class QueryCondition : FilterElementRow {
     }
 
     open class CustomFieldNumberQuery() : ListOfDouble(), CustomFieldRelated {
-        override var customFieldId : String? = null
+        override var customFieldId : String = ""
         override var operator: Operator = Operator.EQUALS
         constructor(customFieldId: String, value: Double): this() {
             this.listOfValues = arrayListOf(value)
@@ -564,7 +564,7 @@ sealed class QueryCondition : FilterElementRow {
         override fun updateValueBy(filterCondition: FilterCondition) {
             super.updateValueBy(filterCondition)
             listOfValues = filterCondition.getValues()
-            customFieldId = filterCondition.stringValue
+            customFieldId = filterCondition.stringValue ?: throw PokerAnalyticsException.QueryValueMapUnexpectedValue
         }
     }
 
@@ -576,10 +576,10 @@ sealed class QueryCondition : FilterElementRow {
 
     class CustomFieldListQuery() : QueryDataCondition<CustomFieldEntry>(), CustomFieldRelated {
         override var entity: Class<CustomFieldEntry> = CustomFieldEntry::class.java
-        override var customFieldId : String? = null
+        override var customFieldId : String = ""
         constructor(customFieldEntry: CustomFieldEntry): this() {
             this.setObject(customFieldEntry)
-            this.customFieldId = customFieldEntry.customField?.id
+            this.customFieldId = customFieldEntry.customField?.id ?: throw PokerAnalyticsException.QueryValueMapUnexpectedValue
         }
 
         override fun entityName(realm: Realm): String {
@@ -589,7 +589,7 @@ sealed class QueryCondition : FilterElementRow {
         override fun updateValueBy(filterCondition: FilterCondition) {
             super.updateValueBy(filterCondition)
             listOfValues = filterCondition.getValues()
-            customFieldId = filterCondition.stringValue
+            customFieldId = filterCondition.stringValue ?: throw PokerAnalyticsException.QueryValueMapUnexpectedValue
         }
     }