chore: clippy and general cleanup of debugger (#3957)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

Clippy fixes along with small changes after #3938 


## Additional Context



## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [ ] I have tested the changes locally.
- [ ] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

tooling/debugger/Cargo.toml

@@ -7,7 +7,6 @@ edition.workspace = true
 license.workspace = true
 
 [build-dependencies]
-rustc_version = "0.4.0"
 build-data.workspace = true
 
 [dependencies]

tooling/debugger/build.rs

@@ -1,24 +1,14 @@
-use rustc_version::{version, Version};
 use std::fs::File;
 use std::io::Write;
 use std::path::{Path, PathBuf};
 use std::{env, fs};
 
-fn check_rustc_version() {
-    assert!(
-        version().unwrap() >= Version::parse("1.71.1").unwrap(),
-        "The minimal supported rustc version is 1.71.1."
-    );
-}
-
 const GIT_COMMIT: &&str = &"GIT_COMMIT";
 
 fn main() {
     // Rebuild if the tests have changed
     println!("cargo:rerun-if-changed=tests");
 
-    check_rustc_version();
-
     // Only use build_data if the environment variable isn't set
     // The environment variable is always set when working via Nix
     if std::env::var(GIT_COMMIT).is_err() {

tooling/debugger/tests/debug.rs

@@ -28,7 +28,7 @@ mod tests {
         dbg_session
             .execute(
                 &format!("{} debug --program-dir {}", nargo_bin, test_program_dir),
-                &format!(".*\\Starting debugger.*"),
+                ".*\\Starting debugger.*",
             )
             .expect("Could not start debugger");
 
@@ -49,7 +49,7 @@ mod tests {
         // having successfully solved the circuit witness.
         dbg_session.send_line("quit").expect("Failed to quit debugger");
         dbg_session
-            .exp_regex(&format!(".*Circuit witness successfully solved.*"))
+            .exp_regex(".*Circuit witness successfully solved.*")
             .expect("Expected circuit witness to be successfully solved.");
     }
 }