Update needed for Rust v1.77.0

error: field `0` is never read
  --> hardware/interfaces/security/authgraph/default/src/main.rs:34:24
   |
34 | struct HalServiceError(String);
   |        --------------- ^^^^^^
   |        |
   |        field in this struct
   |
   = note: `HalServiceError` has derived impls for the traits `Clone` and `Debug`, but these are intenti
onally ignored during dead code analysis
   = note: `-D dead-code` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(dead_code)]`
help: consider changing the field to be of unit type to suppress this warning while preserving the field
 numbering, or remove the field
   |
34 | struct HalServiceError(());
   |                        ~~

error: aborting due to 1 previous error


Test: ./build.py --lto thin

bug: http://b/330185853
Change-Id: I08b79176fb5edea9e24990e4884e521c24660d68