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/tool_signet_miner.py

@@ -20,6 +20,9 @@ CHALLENGE_PRIVATE_KEY = (42).to_bytes(32, 'big')
 
 
 class SignetMinerTest(BitcoinTestFramework):
+    def add_options(self, parser):
+        self.add_wallet_options(parser)
+
     def set_test_params(self):
         self.chain = "signet"
         self.setup_clean_chain = True