WFS layer fails to load when server uses no namespace prefix

[Vrouwenpolder]

Description

When configuring a wfsDatasets entry with an empty featureTypeNamespace (required for WFS servers, such as QGIS Server, that publish feature types without a namespace prefix), the WFS layer fails to load with:

Uncaught TypeError: Cannot read properties of undefined (reading 'getElementsByTagNameNS')
at n.parse (leaflet-wfst.src_custom.js:2:11553)
at n.setFeatureDescription (leaflet-wfst.src_custom.js:2:12745)

Root cause

leaflet-wfst.src_custom.js unconditionally builds the WFS typeName request parameter as:

var typeName = featureTypeNamespace + ':' + featureTypeName;

Even when featureTypeNamespace is an empty string, this still produces a malformed typeName with a stray leading colon (e.g. :layername instead of layername).