On resume session (browser refresh), execution time is lost

[akshayka]

Describe the bug

From @delennc: reconnecting to an active notebook, you lose the info on how long it took to run each cell.

Environment

{
"marimo": "0.4.10",
"OS": "Linux",
"OS Version": "6.5.0-27-generic",
"Processor": "x86_64",
"Python Version": "3.10.12",
"Binaries": {
"Browser": "123.0.6312.122",
"Node": "v18.13.0"
},
"Requirements": {
"click": "8.1.3",
"importlib-resources": "6.1.0",
"jedi": "0.19.0",
"markdown": "3.4.4",
"pymdown-extensions": "10.3",
"pygments": "2.16.1",
"tomlkit": "0.12.0",
"uvicorn": "0.24.0.post1",
"starlette": "0.27.0",
"websocket": "missing",
"typing-extensions": "4.8.0",
"black": "23.3.0"
}
}

Code to reproduce

No response

[mscolnick]

this is because we keep track of the execution time on the frontend. we should move this to the backend into the SessionView (and pass it to the frontend)