bugfix: Strict type checking for RPC boolean parameters

doc/release-notes-26213.md

@@ -0,0 +1,8 @@
+Low-level changes
+=================
+
+- Previously `setban`, `addpeeraddress`, `walletcreatefundedpsbt`, methods
+  allowed non-boolean and non-null values to be passed as boolean parameters.
+  Any string, number, array, or object value that was passed would be treated
+  as false. After this change, passing any value except `true`, `false`, or
+  `null` now triggers a JSON value is not of expected type error. (#26213)