ui_macros: Remove unused module (#30741)

This PR removes an unused module from the `ui_macros` crate.

Release Notes:

- N/A

crates/ui_macros/src/derive_component.rs

@@ -1,98 +0,0 @@
-use convert_case::{Case, Casing};
-use proc_macro::TokenStream;
-use quote::quote;
-use syn::{DeriveInput, Lit, Meta, MetaList, MetaNameValue, NestedMeta, parse_macro_input};
-
-pub fn derive_into_component(input: TokenStream) -> TokenStream {
-    let input = parse_macro_input!(input as DeriveInput);
-    let mut scope_val = None;
-    let mut description_val = None;
-
-    for attr in &input.attrs {
-        if attr.path.is_ident("component") {
-            if let Ok(Meta::List(MetaList { nested, .. })) = attr.parse_meta() {
-                for item in nested {
-                    if let NestedMeta::Meta(Meta::NameValue(MetaNameValue {
-                        path,
-                        lit: Lit::Str(s),
-                        ..
-                    })) = item
-                    {
-                        let ident = path.get_ident().map(|i| i.to_string()).unwrap_or_default();
-                        if ident == "scope" {
-                            scope_val = Some(s.value());
-                        } else if ident == "description" {
-                            description_val = Some(s.value());
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    let name = &input.ident;
-
-    let scope_impl = if let Some(s) = scope_val {
-        let scope_str = s.clone();
-        quote! {
-            fn scope() -> Option<component::ComponentScope> {
-                Some(component::ComponentScope::from(#scope_str))
-            }
-        }
-    } else {
-        quote! {
-            fn scope() -> Option<component::ComponentScope> {
-                None
-            }
-        }
-    };
-
-    let description_impl = if let Some(desc) = description_val {
-        quote! {
-            fn description() -> Option<&'static str> {
-                Some(#desc)
-            }
-        }
-    } else {
-        quote! {}
-    };
-
-    let register_component_name = syn::Ident::new(
-        &format!(
-            "__register_component_{}",
-            Casing::to_case(&name.to_string(), Case::Snake)
-        ),
-        name.span(),
-    );
-    let register_preview_name = syn::Ident::new(
-        &format!(
-            "__register_preview_{}",
-            Casing::to_case(&name.to_string(), Case::Snake)
-        ),
-        name.span(),
-    );
-
-    let expanded = quote! {
-        impl component::Component for #name {
-            #scope_impl
-
-            fn name() -> &'static str {
-                stringify!(#name)
-            }
-
-            #description_impl
-        }
-
-        #[linkme::distributed_slice(component::__ALL_COMPONENTS)]
-        fn #register_component_name() {
-            component::register_component::<#name>();
-        }
-
-        #[linkme::distributed_slice(component::__ALL_PREVIEWS)]
-        fn #register_preview_name() {
-            component::register_preview::<#name>();
-        }
-    };
-
-    expanded.into()
-}