Fix security level for MCAP instances created from HDP plugin

Some health devices without IO capabilities can't connect to MCAP
instances when security level is set to HIGH. This patch enables above
devices to connect to Health instances avoiding the MITM problem.
diff --git a/health/hdp.c b/health/hdp.c
index 137a9e1..a46e211 100644
--- a/health/hdp.c
+++ b/health/hdp.c
@@ -1329,7 +1329,7 @@
 		goto update;
 
 	adapter_get_address(hdp_adapter->btd_adapter, &addr);
-	hdp_adapter->mi = mcap_create_instance(&addr, BT_IO_SEC_HIGH, 0, 0,
+	hdp_adapter->mi = mcap_create_instance(&addr, BT_IO_SEC_MEDIUM, 0, 0,
 					mcl_connected, mcl_reconnected,
 					mcl_disconnected, mcl_uncached,
 					NULL, /* CSP is not used by now */