chore: fix lint cargo::manual_readme

[weihanglo]

See
https://triage.rust-lang.org/gha-logs/rust-lang/rust/98030530980#L2026-08-26T03:05:00.5382785Z-L2026-08-26T03:05:00.5404907Z

This was found in rust-lang/rust#161789

changelog: none

[rustbot]

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[weihanglo]

clippy::cargo-common-metadata lint's behavior conflicts with the new cargo::manual_readme.

 FAILED TEST: tests/ui-cargo/cargo_common_metadata/pass/Cargo.toml
command: CARGO_INCREMENTAL="0" RUSTC_ICE="0" RUSTFLAGS="-Dwarnings -Znext-solver=coherence" "/home/runner/work/rust-clippy/rust-clippy/target/debug/cargo-clippy" "clippy" "--color" "never" "--quiet" "--target-dir" "/home/runner/work/rust-clippy/rust-clippy/target/ui_test/0/tests/ui-cargo/cargo_common_metadata/pass" "--manifest-path" "tests/ui-cargo/cargo_common_metadata/pass/Cargo.toml"

error: no output was expected
Execute `cargo uibless` to update `tests/ui-cargo/cargo_common_metadata/pass/Cargo.stderr` to the actual output
+++ <stderr output>
error: package `cargo_common_metadata_pass` is missing `package.readme` metadata
  |
  = note: `-D clippy::cargo-common-metadata` implied by `-D warnings`
  = help: to override `-D warnings` add `#[allow(clippy::cargo_common_metadata)]`

error: could not compile `cargo_common_metadata_pass` (bin "cargo_common_metadata_pass") due to 1 previous error


full stderr:
error: package `cargo_common_metadata_pass` is missing `package.readme` metadata
  |
  = note: `-D clippy::cargo-common-metadata` implied by `-D warnings`
  = help: to override `-D warnings` add `#[allow(clippy::cargo_common_metadata)]`

To make test pass for now, let just don't deal with clippy::cargo_common_metadata and its tests.