Incorrect retrieved geometry extent from WFS service

[Gpetrak]

When a user tries to load a layer with a different SRID from WGS84 (EPSG 4326) (tested with the projected EPSG: 2100) through WFS, the layer that is loaded on the canvas includes incorrect geometry extent, retrieved from WFS provider.
As a result, QGIS doesn't zoom to the correct geometry extent neither automatically nor by selecting the option zoom to layer.
However, if we search the layer using the correct geometry extent of the layer, we can see that it is loaded correctly.

[Gpetrak]

The incorrect retrieved geometry was because the plugin was adding the layer (from a different SRID) using the corresponding extent from the SRID EPSG:4326. The issue was solved by setting the final extent using the spatial_extent (a well-defined metadata related with the layer extent) right before the layer is added to the map.
The corresponding PR can be found here: #300