Get History Node

[sti0]

Describe the bug
If I set a start and end time and then switching to relative time the start time is actual time - x but end time ist still the previous set time. This leads to false results.

To Reproduce
Steps to reproduce the behavior:

1. Insert a HA history node
2. Select a entity of your choice (I did a binary sensor)
3. Insert start date e.g. 2020-01-04T08:00:00+01:00
4. Insert end date e.g. 2020-01-04T09:00:00+01:00
5. Inject the flow and watch the output. You get the history between 8 and 9 am.
6. Edit the node and check the "Use Relative Time" flag
7. Insert a time e.g. 30m

Expected behavior
I expect to get the last 30m if I use relative time.

Screenshots
If I use fixed times:

If I use a relative time afterwards:

=> enddate should be empty

Example Flow
If applicable, add an example of exported json of a flow exhibiting the issue to aid in reproduction.
[{"id":"a26bd4e2.bed248","type":"inject","z":"d521bfbc.693d2","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":440,"y":160,"wires":[["1fb52ed2.df46d1"]]},{"id":"1fb52ed2.df46d1","type":"api-get-history","z":"d521bfbc.693d2","name":"get history","server":"4d2776f1.5d8f58","startdate":"2020-01-04T08:00:00+01:00","enddate":"2020-01-04T09:00:00+01:00","entityid":"binary_sensor.wsr_buro_contact","entityidtype":"is","useRelativeTime":true,"relativeTime":"30m","flatten":true,"output_type":"array","output_location_type":"msg","output_location":"payload","x":630,"y":160,"wires":[["d0c316da.6aa0e8"]]},{"id":"d0c316da.6aa0e8","type":"debug","z":"d521bfbc.693d2","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":770,"y":220,"wires":[]},{"id":"4d2776f1.5d8f58","type":"server","z":"","name":"Home Assistant","legacy":false,"hassio":true,"rejectUnauthorizedCerts":true,"ha_boolean":"y|yes|true|on|home|open","connectionDelay":true}]

Environment (please complete the following information):

• Node Red Version: v1.0.3
• Node.js Version: ??
• NR Home Assistant Plugin Version: v.5.0.7
• Is Node Red running in Docker: hassio

Other (please complete the following information):

• Have you searched previous issues for duplicates?: yes

Additional context
Add any other context about the problem here.