build: Deny clippy::absolute_paths

Removal of absolute paths is currently in progress. To avoid regressing
those changes add a clippy deny at the workspace level and at the crate
level override with #[expect(clippy::absolute_paths)]

See: #7670

Signed-off-by: Rob Bradford <rbradford@meta.com>

arch/src/lib.rs

@@ -8,6 +8,9 @@
 //! Implements platform specific functionality.
 //! Supported platforms: x86_64, aarch64, riscv64.
 
+// TODO: Trim qualified paths in this crate, then drop this expectation.
+#![expect(clippy::absolute_paths)]
+
 use std::collections::BTreeMap;
 use std::str::FromStr;
 use std::sync::Arc;