Keep device from sleeping while transmitting in range test plugin.

docs/software/plugins/RangeTestPlugin.md

@@ -73,6 +73,9 @@ A: We have a protection in place to keep you from completly filling up your devi
 Q: What do I do with the rangetest.csv file when I'm done?
 A: Go to /static and delete the file.
 
+Q: Can I use this as a sender while on battery power?
+A: Yes, but your battery will run down quicker than normal. While sending, we tell the device not to go into low-power mode since it needs to keep to a fairly strict timer.
+
 # Need more help?
 
 Go to the Meshtastic Discourse Group if you have any questions or to share how you have used this.

src/plugins/RangeTestPlugin.cpp

@@ -1,6 +1,7 @@
 #include "RangeTestPlugin.h"
 #include "MeshService.h"
 #include "NodeDB.h"
+#include "PowerFSM.h"
 #include "RTC.h"
 #include "Router.h"
 #include "configuration.h"
@@ -117,6 +118,9 @@ void RangeTestPluginRadio::sendPayload(NodeNum dest, bool wantReplies)
     memcpy(p->decoded.data.payload.bytes, heartbeatString, p->decoded.data.payload.size);
 
     service.sendToMesh(p);
+
+    // TODO: Handle this better. We want to keep the phone awake otherwise it stops sending.
+    powerFSM.trigger(EVENT_CONTACT_FROM_PHONE);
 }
 
 bool RangeTestPluginRadio::handleReceived(const MeshPacket &mp)