vm-migration: trim qualified paths

Import the std modules used in the crate instead of spelling the full
paths at every use site, and drop the now-unnecessary crate-level
#![expect(clippy::absolute_paths)].

Signed-off-by: Henry Hrvoje Tonkovac <htonkovac@gmail.com>
Assisted-by: Claude:Opus-4.8

vm-migration/src/lib.rs

@@ -3,9 +3,6 @@
 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause
 //
 
-// TODO: Trim qualified paths in this crate, then drop this expectation.
-#![expect(clippy::absolute_paths)]
-
 use std::collections::BTreeMap;
 use std::{io, result};