[processing][grass] Fix broken r.lake algorithm

Author: nyalldawson

python/plugins/processing/algs/grass7/description/r.lake.txt

@@ -3,8 +3,8 @@ Fills lake at given point to given level.
 Raster (r.*)
 QgsProcessingParameterRasterLayer|elevation|Elevation|None|False
 QgsProcessingParameterNumber|water_level|Water level|QgsProcessingParameterNumber.Double|None|False|None|None
-QgsProcessingParameterPoint|coordinates|Seed point coordinates|0,0|False
-QgsProcessingParameterRasterLayer|seed|Raster layer with starting point(s) (at least 1 cell > 0)|None|False
+QgsProcessingParameterPoint|coordinates|Seed point coordinates||True
+QgsProcessingParameterRasterLayer|seed|Raster layer with starting point(s) (at least 1 cell > 0)|None|True
 QgsProcessingParameterBoolean|-n|Use negative depth values for lake raster layer|False
 QgsProcessingParameterRasterDestination|lake|Lake