test: rpc_createmultisig, remove manual wallet initialization

There is no need to manually initialize the wallets within the test
case. The test framework already initializes them when `_requires_wallet`
is true.

test/functional/test_framework/test_framework.py

@@ -444,6 +444,10 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
                 n.createwallet(wallet_name=wallet_name, descriptors=self.options.descriptors, load_on_startup=True)
             n.importprivkey(privkey=n.get_deterministic_priv_key().key, label='coinbase', rescan=True)
 
+    # Only enables wallet support when the module is available
+    def enable_wallet_if_possible(self):
+        self._requires_wallet = self.is_wallet_compiled()
+
     def run_test(self):
         """Tests must override this method to define test logic"""
         raise NotImplementedError