Console: Nothing appears to happen when running code while runtime is starting up

[jmcphers]

To reproduce:

1. Create a new folder with an R file in it containing any R code
2. Add an .Rprofile to the folder with the contents Sys.sleep(10) in it. This will cause R to take 10 seconds to start up.
3. Open the folder in Positron and, while R is starting up, open the R file and try to run some code from it with Cmd + Enter.

The cursor moves down as though the code had been executed, but nothing else happens. When R eventually finishes starting up, the code is executed as you'd expect, but until then there is no feedback that the code was sent to R; it seems like nothing happened.

Screen.Recording.2023-09-21.at.2.12.54.PM.mov

I think that, just as we display code that is queued for execution because the interpreter is busy, we should display code that is queued for execution because the interpreter hasn't started yet.

[kevinushey]

Is it worth considering deferring execution of the .Rprofile, so that we run it only after we've finished some sort of pre-initialization of the runtime?

[jmcphers]

I'm putting this in RC since on Workbench it is likely to take a long time to start R in cases where there's a lot of data to restore/load, and that is going to make long startups more common.

Does not block basic Workbench scenarios so not adding to #1617.