fix(run): makes run never prompt

`watch` and `verify` do prompt the user to actively move to the
next exercise. This change fixes `run` to never prompt. Previously
it was inconsistent between "test" and "compile" exercises.

BREAKING CHANGE: we again change the behavior of the `run` command

tests/fixture/state/finished_exercise.rs

@@ -0,0 +1,5 @@
+// fake_exercise
+
+fn main() {
+
+}

tests/fixture/state/info.toml

@@ -0,0 +1,11 @@
+[[exercises]]
+name = "pending_exercise"
+path = "pending_exercise.rs"
+mode = "compile"
+hint = """"""
+
+[[exercises]]
+name = "pending_test_exercise"
+path = "pending_test_exercise.rs"
+mode = "test"
+hint = """"""

tests/fixture/state/pending_test_exercise.rs

@@ -0,0 +1,4 @@
+// I AM NOT DONE
+
+#[test]
+fn it_works() {}

tests/integration_tests.rs

@@ -1,5 +1,6 @@
 use assert_cmd::prelude::*;
 use glob::glob;
+use predicates::boolean::PredicateBooleanExt;
 use std::fs::File;
 use std::io::Read;
 use std::process::Command;
@@ -136,3 +137,25 @@ fn all_exercises_require_confirmation() {
         ));
     }
 }
+
+#[test]
+fn run_compile_exercise_does_not_prompt() {
+    Command::cargo_bin("rustlings")
+        .unwrap()
+        .args(&["r", "pending_exercise"])
+        .current_dir("tests/fixture/state")
+        .assert()
+        .code(0)
+        .stdout(predicates::str::contains("I AM NOT DONE").not());
+}
+
+#[test]
+fn run_test_exercise_does_not_prompt() {
+    Command::cargo_bin("rustlings")
+        .unwrap()
+        .args(&["r", "pending_test_exercise"])
+        .current_dir("tests/fixture/state")
+        .assert()
+        .code(0)
+        .stdout(predicates::str::contains("I AM NOT DONE").not());
+}