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/mempool_persist.py

@@ -60,7 +60,6 @@ class MempoolPersistTest(BitcoinTestFramework):
         if self.is_wallet_compiled():
             self.nodes[2].createwallet(
                 wallet_name="watch",
-                descriptors=True,
                 disable_private_keys=True,
                 load_on_startup=False,
             )