String concatenation expression transformed into math additions

[aaime]

Describe the bug When using string concantenation to generate a label from multiple fields in QGIS, it's possible to use the "+" operator. Exporting it, the generated OGC Filter expression is a ogc:Add rather than a Concatenate function.

To Reproduce

The following screenshot shows the input, the generated map, and the generated SLD:

Expected behavior The plugin should recognize the different context and generate a string concatenation expression.

Environment info (please complete the following information):

• OS: Widnows
• QGIS version: 3.23
• Bridge version: 4.4.1
• Python version: whatever is coming with the QGIS installer

[GeoSander]

Good catch @aaime, this should definitely be fixed especially for labeling scenarios (which I believe is how you discovered this in the first place).

Since the style conversion actually happens in bridge-style and not in qgis-bridge-plugin, I took the liberty to transfer your issue.