scripted-diff: test: remove 'descriptors=True' argument for createwallet calls

Descriptor wallets are already created by default since v23.0, but
since the recent legacy wallet removal this parameter *must* be True
(see commit 9f04e02ffa), i.e. still
passing it wouldn't contain any information for test readers
anymore. So simply drop them in the functional tests in order to
reduce code bloat.

-BEGIN VERIFY SCRIPT-
sed -i 's/, descriptors=True//g' $(git ls-files -- 'test/functional' ':(exclude)test/functional/wallet_backwards_compatibility.py')
sed -i '/descriptors=True,/d' ./test/functional/mempool_persist.py
-END VERIFY SCRIPT-

test/functional/wallet_listsinceblock.py

@@ -421,7 +421,7 @@ class ListSinceBlockTest(BitcoinTestFramework):
         # Create a watchonly wallet tracking two multisig descriptors.
         multi_a = descsum_create("wsh(multi(1,tpubD6NzVbkrYhZ4YBNjUo96Jxd1u4XKWgnoc7LsA1jz3Yc2NiDbhtfBhaBtemB73n9V5vtJHwU6FVXwggTbeoJWQ1rzdz8ysDuQkpnaHyvnvzR/*,tpubD6NzVbkrYhZ4YHdDGMAYGaWxMSC1B6tPRTHuU5t3BcfcS3nrF523iFm5waFd1pP3ZvJt4Jr8XmCmsTBNx5suhcSgtzpGjGMASR3tau1hJz4/*))")
         multi_b = descsum_create("wsh(multi(1,tpubD6NzVbkrYhZ4YHdDGMAYGaWxMSC1B6tPRTHuU5t3BcfcS3nrF523iFm5waFd1pP3ZvJt4Jr8XmCmsTBNx5suhcSgtzpGjGMASR3tau1hJz4/*,tpubD6NzVbkrYhZ4Y2RLiuEzNQkntjmsLpPYDm3LTRBYynUQtDtpzeUKAcb9sYthSFL3YR74cdFgF5mW8yKxv2W2CWuZDFR2dUpE5PF9kbrVXNZ/*))")
-        self.nodes[0].createwallet(wallet_name="wo", descriptors=True, disable_private_keys=True)
+        self.nodes[0].createwallet(wallet_name="wo", disable_private_keys=True)
         wo_wallet = self.nodes[0].get_wallet_rpc("wo")
         wo_wallet.importdescriptors([
             {