[tests] Fix test of launch with bridges.

The text of the error given when there is no default interface
for bridging set changed and the test should reflect it.

tests/test_daemon.cpp

@@ -1914,7 +1914,7 @@ TEST_F(Daemon, refuses_launch_bridged_without_setting)
     std::stringstream err_stream;
     send_command({"launch", "--network", "bridged"}, trash_stream, err_stream);
     EXPECT_THAT(err_stream.str(),
-                HasSubstr("You have to `multipass set local.bridged-network=<name>` to use the `--bridged` shortcut."));
+                HasSubstr("You have to `multipass set local.bridged-network=<name>` to use the \"bridged\" shortcut."));
 }
 
 TEST_F(Daemon, refuses_launch_with_invalid_bridged_interface)