Trigger redraw_status_line when waiting

[sontungexpt]

I am trying to implement the statusline for codeium status.
According to the documentation we has three state "idle", "waiting", and "completions" and we should register update callback by calling

require("codeium.virtual_text").set_statusbar_refresh(function()
 --- do something here
end)

But I realize that I never receive "waiting".
The status flips directly between "idle" and "completions", with no intermediate state.

So I created this PR for fixed this problem.

[CLAassistant]

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