Skip strum in regular nu-protocol build (#9445)

# Description
`derive(EnumIter)` is only required to run completeness tests.
Thus make the derive conditional on test and move `strum` and
`strum_macros` to the dev dependencies.

## Is it worth it?

Removing this derive does not change the binary size (checked via `cargo
bloat --crates` from `cargo-bloat`).
Compile time change is below a second so hard to judge based on a single
run of `cargo clean --profile dev; cargo build --timings`
Unsure if this negatively impacts how incremental compilation can
recompile when you switch between `cargo build`/`run` and `cargo test`
in your local workflow.

To get rid of `strum`/`strum_macros` as a proc macro crate we would need
to also remove it from `reedline`.
Further more a crate in the `polars` dependency tree uses `strum`
(curently not as relevant for the 1.0 build).

crates/nu-protocol/src/ty.rs

@@ -1,11 +1,13 @@
 use serde::{Deserialize, Serialize};
+#[cfg(test)]
 use strum_macros::EnumIter;
 
 use std::fmt::Display;
 
 use crate::SyntaxShape;
 
-#[derive(Clone, Debug, Default, EnumIter, PartialEq, Eq, Serialize, Deserialize, Hash)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, Hash)]
+#[cfg_attr(test, derive(EnumIter))]
 pub enum Type {
     Any,
     Binary,