Completion suggestions in string interpolation shouldn't include void expressions

[parlough]

void main() {
  print('Test: ${ot^}');
}

void other() { }

Results in:

void main() {
  print('Test: ${other()}');
}

other should either not be suggested here, or if it is, it should generate a tear off. But I think it's rare to want to include a tear off in a string, so it's probably fine to just not suggest it.

Tested on current main: cb16f98

Reproduced with IJ and VSCode.

Doesn't affect 3.2 stable, where the void function is not suggested at all.