Remove unused Idsig struct to facilitate Rust update

The Rust update cl is aosp/3007766

Bug: 330185853
Test: atest vm.test
Change-Id: I94b006748ed4c4242076e55971618167f961b3a8
diff --git a/vm/src/main.rs b/vm/src/main.rs
index 063f992..bc05ec3 100644
--- a/vm/src/main.rs
+++ b/vm/src/main.rs
@@ -33,9 +33,6 @@
 use std::num::NonZeroU16;
 use std::path::{Path, PathBuf};
 
-#[derive(Debug)]
-struct Idsigs(Vec<PathBuf>);
-
 #[derive(Args, Default)]
 /// Collection of flags that are at VM level and therefore applicable to all subcommands
 pub struct CommonConfig {