Add a test to restart the app

[evan-forbes]

Description

In the past, we've ran into at least two bugs that resulted in a panic after restarting (one being #3336).

Acceptance criteria

• Unit test that starts stops and restarts a node. If a unit test format is not possible e2e test will also do

[cmwaters]

Good shout. it's hard to do a full reboot as a unit test. I think this would be better suited as a knuu test.

In cometbft's test they include perturbations which involve killing and restarting the docker instance

[evan-forbes]

we might be able to with testnode if we manually call these and shutdown, then restart

celestia-app/test/util/testnode/network.go

Lines 36 to 43 in 9db2f8b

	cctx, stopNode, err := StartNode(tmNode, cctx)
	require.NoError(t, err)
	cctx, cleanupGRPC, err := StartGRPCServer(app, cfg.AppConfig, cctx)
	require.NoError(t, err)
	apiServer, err := StartAPIServer(app, *cfg.AppConfig, cctx)
	require.NoError(t, err)

that might not work tho, in which case I agree, knuu is the way to go

[cmwaters]

FYI, I think the upgrade tests already kill the node and restart it