paths: Replace lazy_static! with OnceLock (#13213)

This PR replaces the `lazy_static!` usages in the `paths` crate with
`OnceLock` from the standard library.

This allows us to drop the `lazy_static` dependency from this crate.

The paths are now exposed as accessor functions that reference a private
static value.

Release Notes:

- N/A

crates/client/src/client.rs

@@ -509,7 +509,7 @@ impl Client {
         let credentials_provider: Arc<dyn CredentialsProvider + Send + Sync + 'static> =
             if use_zed_development_auth {
                 Arc::new(DevelopmentCredentialsProvider {
-                    path: paths::CONFIG_DIR.join("development_auth"),
+                    path: paths::config_dir().join("development_auth"),
                 })
             } else {
                 Arc::new(KeychainCredentialsProvider)