Default `#[schemars(deny_unknown_fields)] for json-language-server schemas (#33883)

Followup to #33678, doing the same thing for all JSON Schema files
provided to json-language-server

Release Notes:

* Added warnings for unknown fields when editing `tasks.json` /
`snippets.json`.

crates/theme/src/settings.rs

@@ -12,9 +12,10 @@ use gpui::{
 use refineable::Refineable;
 use schemars::{JsonSchema, json_schema};
 use serde::{Deserialize, Serialize};
-use settings::{ParameterizedJsonSchema, Settings, SettingsSources, replace_subschema};
+use settings::{ParameterizedJsonSchema, Settings, SettingsSources};
 use std::sync::Arc;
 use util::ResultExt as _;
+use util::schemars::replace_subschema;
 
 const MIN_FONT_SIZE: Pixels = px(6.0);
 const MIN_LINE_HEIGHT: f32 = 1.0;