Fix database handling issues

SignalServiceKit/src/Loki/API/LokiAPI.swift

@@ -142,7 +142,7 @@ public final class LokiAPI : NSObject {
                 destinations.append(contentsOf: slaveDestinations)
                 seal.fulfill(destinations)
             }
-            if let transaction = transaction {
+            if let transaction = transaction, transaction.connection.pendingTransactionCount != 0 {
                 getDestinationsInternal(in: transaction)
             } else {
                 storage.dbReadConnection.read { transaction in

SignalServiceKit/src/Loki/API/LokiDotNetAPI.swift

@@ -57,7 +57,7 @@ public class LokiDotNetAPI : NSObject {
         func setAuthTokenInternal(in transaction: YapDatabaseReadWriteTransaction) {
             transaction.setObject(newValue, forKey: server, inCollection: authTokenCollection)
         }
-        if let transaction = transaction {
+        if let transaction = transaction, transaction.connection.pendingTransactionCount != 0 {
             setAuthTokenInternal(in: transaction)
         } else {
             storage.dbReadWriteConnection.readWrite { transaction in

SignalServiceKit/src/Loki/API/LokiFileServerAPI.swift

@@ -76,9 +76,16 @@ public final class LokiFileServerAPI : LokiDotNetAPI {
                     }
                 })
             }.map(on: DispatchQueue.global()) { deviceLinks -> Set<DeviceLink> in
-                storage.dbReadWriteConnection.readWrite { transaction in
+                func setDeviceLinks(in transaction: YapDatabaseReadWriteTransaction) {
                     storage.setDeviceLinks(deviceLinks, in: transaction)
                 }
+                if let transaction = transaction, transaction.connection.pendingTransactionCount != 0 {
+                    setDeviceLinks(in: transaction)
+                } else {
+                    storage.dbReadWriteConnection.readWrite { transaction in
+                        setDeviceLinks(in: transaction)
+                    }
+                }
                 return deviceLinks
             }
         }