ProfilerUI: Added a warning when trying to compile and the variables are not declared

[matburnx]

Fixes https://github.com/pharo-project/pharo/issues/16330 As the code we are compiling doesn't belong to any class, the compiler cannot change the definition of the code. A workaround that we found is showing a warning to the user when that happens. A more complete solution can be to implement a binding mechanism like in the Playground, but that needs more discussion.