[processing] use complex delimiter for interpolation data to avoid

overlaps with charactes which can be used in the layers source URI (fix #20490)

(cherry picked from commit 17fd86e)

python/plugins/processing/algs/qgis/IdwInterpolation.py

@@ -129,7 +129,7 @@ def processAlgorithm(self, parameters, context, feedback):
 
         layerData = []
         layers = []
-        for row in interpolationData.split(';'):
+        for row in interpolationData.split('::|::'):
             v = row.split('::~::')
             data = QgsInterpolator.LayerData()
 

python/plugins/processing/algs/qgis/TinInterpolation.py

@@ -145,7 +145,7 @@ def processAlgorithm(self, parameters, context, feedback):
         layerData = []
         layers = []
         crs = QgsCoordinateReferenceSystem()
-        for row in interpolationData.split(';'):
+        for row in interpolationData.split('::|::'):
             v = row.split('::~::')
             data = QgsInterpolator.LayerData()
 

python/plugins/processing/algs/qgis/ui/InterpolationWidgets.py

@@ -203,10 +203,10 @@ def value(self):
                 else:
                     inputType = QgsInterpolator.SourceBreakLines
 
-            layers += '{}::~::{:d}::~::{:d}::~::{:d};'.format(layer.source(),
-                                                              interpolationSource,
-                                                              fieldIndex,
-                                                              inputType)
+            layers += '{}::~::{:d}::~::{:d}::~::{:d}::|::'.format(layer.source(),
+                                                                  interpolationSource,
+                                                                  fieldIndex,
+                                                                  inputType)
         return layers[:-1]