Change device isolation mode to set errorOnVerifiedUserProblems to false (#104)

https://github.com/element-hq/matrix-react-sdk/pull/92 changed the default mode
for encryption to throw an error when sending a message and the room contains either:
 - a verified user with an unverified device
 - a verifeid user who has changed their identity.

We're not really ready for this (we lack the UI to deal with it), so roll that
back.

test/settings/controllers/DeviceIsolationModeController-test.ts

@@ -27,7 +27,7 @@ describe("DeviceIsolationModeController", () => {
             const cli = stubClient();
             const controller = new DeviceIsolationModeController();
             controller.onChange(SettingLevel.DEVICE, "", false);
-            expect(cli.getCrypto()?.setDeviceIsolationMode).toHaveBeenCalledWith(new AllDevicesIsolationMode(true));
+            expect(cli.getCrypto()?.setDeviceIsolationMode).toHaveBeenCalledWith(new AllDevicesIsolationMode(false));
         });
     });
 });