Fix test_list_files_for_qfield_broken_file test by still uploading a broken QGS file, but with proper first tag

Before we didn't care about the actual contents of the project file,
but now we need the root `<qgis />` tag to be present to accept the QGIS project file.

Author: suricactus

docker-app/qfieldcloud/core/tests/testdata/delta/broken.qgs

@@ -1,11 +1,23 @@
 <!DOCTYPE qgis PUBLIC 'http://mrcc.com/qgis.dtd' 'SYSTEM'>
-
+<qgis projectname="" saveDateTime="2023-03-20T00:00:48" saveUser="suricactus" saveUserFull="Ivan Ivanov" version="3.30.0-'s-Hertogenbosch">
+  <homePath path=""></homePath>
+  <title></title>
+  <transaction mode="Disabled"></transaction>
+  <projectFlags set=""></projectFlags>
+  <projectCrs>
+    <spatialrefsys nativeFormat="Wkt">
+      <wkt>GEOGCRS["WGS 84",ENSEMBLE["World Geodetic System 1984 ensemble",MEMBER["World Geodetic System 1984 (Transit)"],MEMBER["World Geodetic System 1984 (G730)"],MEMBER["World Geodetic System 1984 (G873)"],MEMBER["World Geodetic System 1984 (G1150)"],MEMBER["World Geodetic System 1984 (G1674)"],MEMBER["World Geodetic System 1984 (G1762)"],MEMBER["World Geodetic System 1984 (G2139)"],ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]],ENSEMBLEACCURACY[2.0]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["geodetic latitude (Lat)",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["geodetic longitude (Lon)",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],USAGE[SCOPE["Horizontal component of 3D system."],AREA["World."],BBOX[-90,-180,90,180]],ID["EPSG",4326]]</wkt>
+      <proj4>+proj=longlat +datum=WGS84 +no_defs</proj4>
+      <srsid>3452</srsid>
+      <srid>4326</srid>
+      <authid>EPSG:4326</authid>
+      <description>WGS 84</description>
       <projectionacronym>longlat</projectionacronym>
       <ellipsoidacronym>EPSG:7030</ellipsoidacronym>
       <geographicflag>true</geographicflag>
     </spatialrefsys>
   </projectCrs>
-  <layer-tree-group>
+  <!-- <layer-tree-group> -- XML is broken here, there will be closing tag, but the opening one is commented -->
     <customproperties/>
     <layer-tree-layer providerKey="ogr" name="polygons" expanded="1" checked="Qt::Checked" id="polygons_5096fc7b_b106_4740_90b4_9de822382d71" legend_exp="" source="./polygons.geojson">
       <customproperties/>