LocalPreferences.toml disable = true is not reliable

[sjdaines]

Just adding

[TruncatedStacktraces]
disable = true

to LocalPreferences.toml and then restarting the Julia REPL is apparently not sufficient to disable TruncatedStacktraces
(if TruncatedStacktraces is not part of the environment, ie is present in Manifest.toml but not Project.toml).

It does work if TruncatedStacktraces is also added to the environment

(this is testing with Julia 1.8.3)