The functional test feature_rbf.py currently fails on master branch, if descriptor wallets are used (argument --descriptors). This is due to the fact that in this case, a call to the helper init_wallet
creates a wallet without rescanning the blockchain; the test framework maps the importprivkey RPC calls to the importdescriptors RPC without rescanning by default (timestamp='now'). Fix this by always calling with rescan=True, which calls importdescriptors with timestamp=0. Also add feature_rbf.py --descriptors to the list of the test runner's calls.
Fixes #23563.