misc: Fix beta clippy issues

Fixed with 'cargo clippy --fix' mostly.

Signed-off-by: Bo Chen <bchen@crusoe.ai>

test_infra/src/lib.rs

@@ -1229,18 +1229,14 @@ impl Guest {
     }
 }
 
+#[derive(Default)]
 pub enum VerbosityLevel {
+    #[default]
     Warn,
     Info,
     Debug,
 }
 
-impl Default for VerbosityLevel {
-    fn default() -> Self {
-        Self::Warn
-    }
-}
-
 impl Display for VerbosityLevel {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         use VerbosityLevel::*;