Fixes issue where a pending session was messing with the month criteria

app/src/main/java/net/pokeranalytics/android/model/Criteria.kt

@@ -171,8 +171,8 @@ sealed class Criteria(override var uniqueIdentifier: Int) : IntIdentifiable, Row
 			return when (this) {
 				is AllMonthsUpToNow -> {
 					val realm = Realm.getDefaultInstance()
-					val firstSession = realm.where<Session>().sort("startDate", Sort.ASCENDING).findFirst()
-					val lastSession = realm.where<Session>().sort("startDate", Sort.DESCENDING).findFirst()
+					val firstSession = realm.where<Session>().isNotNull("startDate").sort("startDate", Sort.ASCENDING).findFirst()
+					val lastSession = realm.where<Session>().isNotNull("startDate").sort("startDate", Sort.DESCENDING).findFirst()
 					realm.close()
 
 					val years: ArrayList<Query> = arrayListOf()