Sensor data not recorded if GPS enabled but speed is zero

Related to #1088. When I stop moving for a few minutes (with GPS on) I see suspicious linear interpolation for every metric:

Red is HR, blue is speed, green is elevation.

If the phone is not moving then dropping redundant GPS coords makes sense, but HR data is still useful and it should be recorded. The speed should probably be recorded as being 0 at the start and end of each interval to avoid weird interpolation, then it would correctly show as 0 over the whole interval and if other applications want to interpolate the data it'll be unambiguously 0.

Here is a snippet of exported kml. No data exists for the intervals where I've stopped moving.

<when>2024-07-18T15:55:31.136+00:00</when>
<coord>xxx.xxxx23 xx.xxxx27 9.313198332140</coord>

<when>2024-07-18T15:55:32.14+00:00</when>
<coord>xxx.xxxx18 xx.xxxx38 8.9174764139130</coord>

<when>2024-07-18T15:55:33.139+00:00</when>
<coord>xxx.xxxx09 xx.xxxx45 8.2689896704566</coord>

<!-- gap of 29.952 seconds -->

<when>2024-07-18T15:56:03.091+00:00</when>
<coord>xxx.xxxx05 xx.xxxx48 9.444981316744</coord>

<when>2024-07-18T15:56:03.153+00:00</when>
<coord>xxx.xxxx05 xx.xxxx48 9.444981316744</coord>

<!-- gap of 110.974 seconds -->

<when>2024-07-18T15:57:54.127+00:00</when>
<coord>xxx.xxxx19 xx.xxxx42 8.5567704015492</coord>

<when>2024-07-18T15:57:55.122+00:00</when>
<coord>xxx.xxxx21 xx.xxxx51 8.6911931082478</coord>

My settings:	Setting	Value
Recording > Recording distance interval	1 m
Recording > Idle threshold	30 s
Recording > Max distance	200 m
Sensors > GPS > Sampling time interval	0 s
Sensors > GPS > GPS accuracy	20 m

Checklist

[x] Consulted [https://dontkillmyapp.com/]
[x] Power management: battery optimization is disabled for OpenTracks

Technical information

Device: Google Pixel 8
OS: GrapheneOS 2024-07-28
OpenTracks version: v4.12.5

OpenTracksApp / OpenTracks

Sensor data not recorded if GPS enabled but speed is zero #1966