fix(network): prevent null multiplayer peer crashes offline/teardown and fix Nakama RPC session validation

test_suite/tests/client_test.gd

@@ -0,0 +1,32 @@
+extends "res://base_test.gd"
+
+func setup():
+	var username = str(randi_range(1000, 100000))
+	var client = Nakama.create_client(Config.SERVER_KEY, Config.HOST, Config.PORT, Config.SCHEME)
+	# POST
+	var session = await client.authenticate_custom_async("MyIdentifier")
+	if assert_cond(session.is_valid()) or assert_cond(!session.is_expired()):
+		return
+	# PUT
+	var update = await client.update_account_async(session, username)
+	if assert_false(update.is_exception()):
+		return
+	# GET
+	var account : NakamaAPI.ApiAccount = await client.get_account_async(session)
+	if assert_false(account.is_exception()):
+		return
+	if assert_cond(account.user.username == username):
+		return
+	# POST - DELETE
+	var group : NakamaAPI.ApiGroup = await client.create_group_async(session, "MyGroupName3")
+	if assert_false(group.is_exception()):
+		return
+	var delete = await client.delete_group_async(session, group.id)
+	if assert_false(delete.is_exception()):
+		return
+	# All good
+	done()
+	return
+
+func _process(_delta):
+	assert_time(3)