Enable clippy::drain_collect (#8745)

This PR enables the
[`clippy::drain_collect`](https://rust-lang.github.io/rust-clippy/master/index.html#/drain_collect)
rule and fixes the outstanding violations.

Release Notes:

- N/A

tooling/xtask/src/main.rs

@@ -89,7 +89,6 @@ fn run_clippy(args: ClippyArgs) -> Result<()> {
         "clippy::default_constructed_unit_structs",
         "clippy::derivable_impls",
         "clippy::derive_ord_xor_partial_ord",
-        "clippy::drain_collect",
         "clippy::eq_op",
         "clippy::expect_fun_call",
         "clippy::explicit_auto_deref",