test: create default wallet in extended tests

This was omitted from #15454

test/functional/feature_pruning.py

@@ -81,16 +81,16 @@ class PruneTest(BitcoinTestFramework):
 
         # Create nodes 0 and 1 to mine.
         # Create node 2 to test pruning.
-        self.full_node_default_args = ["-maxreceivebuffer=20000", "-checkblocks=5"]
+        self.full_node_default_args = ["-maxreceivebuffer=20000", "-checkblocks=5", "-wallet="]
         # Create nodes 3 and 4 to test manual pruning (they will be re-started with manual pruning later)
         # Create nodes 5 to test wallet in prune mode, but do not connect
         self.extra_args = [
             self.full_node_default_args,
             self.full_node_default_args,
-            ["-maxreceivebuffer=20000", "-prune=550"],
-            ["-maxreceivebuffer=20000"],
-            ["-maxreceivebuffer=20000"],
-            ["-prune=550"],
+            ["-wallet=", "-maxreceivebuffer=20000", "-prune=550"],
+            ["-wallet=", "-maxreceivebuffer=20000"],
+            ["-wallet=", "-maxreceivebuffer=20000"],
+            ["-wallet=", "-prune=550"],
         ]
         self.rpc_timeout = 120