No Cycle Slips in OBS RINEX from MP

#### Issue details
rinex observation output file does not write the LLI bit since it is hard coded to "0"

looking at this line https://github.com/ArduPilot/MissionPlanner/blob/c1b3d075003578e2810e78321e79f8dbee2400ad/ExtLibs/Utilities/LogOutput.cs#L593

the LLI bit is permanently set to "0" but never changed. Hence when coming across a GRXS message and writing the OBS rinex file, It should look at if the LLI bit on the GRAW message changed - but it doesn't. It stays fixed at "0".

That way, even if the LLI on the GRAW is changed due to a cycle slip, the OBS output file does not reflect that.

This is an example of an observation from M8P and an addition Emlid M+ that was on board alongside the main UAV M8P GPS. Although these are 2 different GPS receivers, they were both at same place and time. So assuming one saw cycle slips (red tick marks)- the other should have probably seen some as well.


Question:
When looking at logs, I only saw GRXS messages but didn't see any GRAW messages. What is the way to get GRAW messages to be written to the log? In my case the GPS_Type parameter was set to "1", i.e. AUTO. Should it be set to "2" for uBlox in order to get GRAW messages out?

#### Version
1.3.74
#### Platform
[ ] All
[ ] AntennaTracker
[ x ] Copter
[ ] Plane
[ ] Rover
[ ] Sub

#### Airframe type
Quad

#### Hardware type
Pixhawk1

#### Logs
[test_pixhawk_log.log](https://github.com/ArduPilot/MissionPlanner/files/6018316/test_pixhawk_log.log)
[test_obs_file.obs.log](https://github.com/ArduPilot/MissionPlanner/files/6018321/test_obs_file.obs.log)

Start in ExtLibs/Utilities/LogOutput.cs at the linked line around 593, then compare the supplied test_pixhawk_log.log and test_obs_file.obs.log for GRXS/GRAW and LLI values. Trace how the observation output is produced and verify that the OBS file reflects relevant LLI changes, including cycle slips, when the behavior is corrected.

Written by the indexing model from the issue text.