test: Clear forced -walletdir setting after wallet init_tests

Leaving this value set interfered with the CreateWallet test if it happened to execute later in the test ordering. Specifically it would cause CreateWallet test to write data to the current directory instead of temporary test directory.

src/wallet/test/init_test_fixture.cpp

@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <fs.h>
+#include <univalue.h>
 #include <util/check.h>
 #include <util/system.h>
 
@@ -37,6 +38,9 @@ InitWalletDirTestingSetup::InitWalletDirTestingSetup(const std::string& chainNam
 
 InitWalletDirTestingSetup::~InitWalletDirTestingSetup()
 {
+    gArgs.LockSettings([&](util::Settings& settings) {
+        settings.forced_settings.erase("walletdir");
+    });
     fs::current_path(m_cwd);
 }