test: Fix feature_index_prune.py to work with new blockfilterindex defaults

Node 1 was configured with only -coinstatsindex=1, but with the new
defaults it was also getting -blockfilterindex=basic enabled. The test
expects node 1 to only have coinstatsindex, so we need to explicitly
disable blockfilterindex and peerblockfilters.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: PastaPastaPasta

test/functional/feature_index_prune.py

@@ -22,7 +22,7 @@ def set_test_params(self):
         self.num_nodes = 4
         self.extra_args = [
             ["-fastprune", "-prune=1", "-blockfilterindex=1"] + DEPLOYMENT_ARGS,
-            ["-fastprune", "-prune=1", "-coinstatsindex=1"] + DEPLOYMENT_ARGS,
+            ["-fastprune", "-prune=1", "-coinstatsindex=1", "-blockfilterindex=0", "-peerblockfilters=0"] + DEPLOYMENT_ARGS,
             ["-fastprune", "-prune=1", "-blockfilterindex=1", "-coinstatsindex=1"] + DEPLOYMENT_ARGS,
             [] + DEPLOYMENT_ARGS,
         ]