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/wallet_importdescriptors.py

@@ -30,6 +30,9 @@ from test_framework.wallet_util import (
 )
 
 class ImportDescriptorsTest(BitcoinTestFramework):
+    def add_options(self, parser):
+        self.add_wallet_options(parser, legacy=False)
+
     def set_test_params(self):
         self.num_nodes = 2
         self.extra_args = [["-addresstype=legacy"],