ci: run clippy using cargo-all-features

Turns out any cargo subcommand can be ran like this, instead of just the
ones documented on the cargo-all-features crates.io page.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

.buildkite/test_description.json

@@ -73,7 +73,7 @@
     },
     {
       "test_name": "clippy",
-      "command": "cargo clippy --workspace --all-features --all-targets -- -D warnings -D clippy::undocumented_unsafe_blocks",
+      "command": "cargo all-features clippy --workspace --all-targets -- -D warnings -D clippy::undocumented_unsafe_blocks",
       "platform": [
         "x86_64",
         "aarch64",