When value relation widget is in completer mode the text "(no selection)" should disappear on selection in stead of staying in the box as text

[RobinRots]

Description

When the value relation widget is set up in completer mode it would be more user-friendly to have the text "(no selection)" disappear as soon the box is selected (thus starting with an empty text field). This saves you the trouble of having to delete "(no selection)" before you can start typing what you want (same as you don't have to delete "NULL" in the text edit widget when you want to change an attribute that happens to have a NULL value)

How to Reproduce

see bugreport_completer_noselection.zip

Open the poject
Open the attribute table "value_relation_example" and put it in form-mode if it wouldn't be
Select the feature in the left panel with fid "1", it should have "(no selection)" in the column "with_completer"
When you now want to change the "(no selection)" value by clicking its box in the form, the text "(no selection)" stays there as text which you first have to delete before you can start typing what you want.

QGIS and OS versions

QGIS version	3.16.0-Hannover	QGIS code revision	43b64b1
Compiled against Qt	5.11.2	Running against Qt	5.11.2
Compiled against GDAL/OGR	3.1.4	Running against GDAL/OGR	3.1.4
Compiled against GEOS	3.8.1-CAPI-1.13.3	Running against GEOS	3.8.1-CAPI-1.13.3
Compiled against SQLite	3.29.0	Running against SQLite	3.29.0
PostgreSQL Client Version	11.5	SpatiaLite Version	4.3.0
QWT Version	6.1.3	QScintilla2 Version	2.10.8
Compiled against PROJ	6.3.2	Running against PROJ	Rel. 6.3.2, May 1st, 2020
OS Version	Windows 10 (10.0)
Active python plugins	autoSaver; geopunt4Qgis; OSMDownloader; qfieldsync; qgis-maptiler-plugin; quick_map_services; SelectWithin; splitmultipart; SpreadsheetLayers; db_manager; MetaSearch; processing

Additional context
This feature request relates to the bugfix for bug #38801.

[ghtmtt]

still valid in QGIS 3..34. Shouldn't this ticket converted into a bug report instead of a feature request?