Fatal untwine error is not shown to the user

[kannes]

Describe the bug
I tried to add a point cloud, now I see just the red extent lines and no points. Tried to find out why I found this error in the stderr of my QGIS invocation:
untwine fatal error: writers.las: Unable to convert scaled value (-2632650671) to int32 for dimension 'Z' when writing LAS/LAZ file /tmp/ept_MYLAZFILEBASENAME/ept-data/4-2-4-2.laz.

I got no error message in QGIS itself and the Log Messages for "Point clouds" only shows INFO messages to me.

I think an error message should prominently be displayed to the user and the log messages should also include it? Not sure what kind of error I encountered there though.

How to Reproduce
Try to load a LAZ file with particular values, I guess? Not sure. I could provide sample data in a private channel.

QGIS and OS versions

QGIS version	3.19.0-Master	QGIS code revision	8a9ea53
Compiled against Qt	5.15.2	Running against Qt	5.15.2
Compiled against GDAL/OGR	3.0.4	Running against GDAL/OGR	3.0.4
Compiled against GEOS	3.8.1-CAPI-1.13.3	Running against GEOS	3.8.1-CAPI-1.13.3
Compiled against SQLite	3.34.1	Running against SQLite	3.34.1
Compiled against PDAL	2.2.0	Running against PDAL	2.2.0 (git-version: Release)
PostgreSQL Client Version	13.2	SpatiaLite Version	4.3.0a
QWT Version	6.1.6	QScintilla2 Version	2.11.6
Compiled against PROJ	6.3.2	Running against PROJ	Rel. 6.3.2, May 1st, 2020
OS Version	Arch Linux

[wonder-sk]

@kannes Could you please share link to the test file privately with me? martin.dobias at lutraconsulting.co.uk

There's a pending task to show errors when untwine fails - wonder-sk/point-cloud-experiments#73 - unfortunately we have not implemented that yet...

[wonder-sk]

Upstream issue: hobuinc/untwine#53

[wonder-sk]

Another upstream issue to add error reporting in untwine: hobuinc/untwine#54 - once that is implemented, we can add error reporting on QGIS side.