test: Remove wallet option from non-wallet tests

Review note: The changes are complete, because self.options.descriptors
is set to None in parse_args (test_framework.py).

A value of None implies -disablewallet, see the previous commit.

So if a call to add_wallet_options is missing, it will lead to a test
failure when the wallet is compiled in.

test/functional/rpc_psbt.py

@@ -47,8 +47,9 @@ import json
 import os
 
 
-# Create one-input, one-output, no-fee transaction:
 class PSBTTest(BitcoinTestFramework):
+    def add_options(self, parser):
+        self.add_wallet_options(parser)
 
     def set_test_params(self):
         self.num_nodes = 3