🎚️ feat: Custom Parameters (#7342)

* #

* - refactor: simplified getCustomConfig func

* #

* - feature: persist values for parameters with optionType of custom

* #

* - refactor: moved `Parameters/settings.ts` into `data-provider` so that both frontend and backend code can use it.

* - feature: loadCustomConfig can now parse and validate customParams property for `endpoints.custom` in `librechat.yaml`

* # fixed linter

* # removed .strict() in config.ts

* change: added packages/data-provider/src to SOURCE_DIRS for i18n check

* # removed unnecessary lodash imports

* # addressed PR comments
# fixed lint for updated files

* # better import for lodash (w/o relying on tree-shaking)

api/server/services/Config/getCustomConfig.js

@@ -10,17 +10,7 @@ const getLogStores = require('~/cache/getLogStores');
  * */
 async function getCustomConfig() {
   const cache = getLogStores(CacheKeys.CONFIG_STORE);
-  let customConfig = await cache.get(CacheKeys.CUSTOM_CONFIG);
-
-  if (!customConfig) {
-    customConfig = await loadCustomConfig();
-  }
-
-  if (!customConfig) {
-    return null;
-  }
-
-  return customConfig;
+  return (await cache.get(CacheKeys.CUSTOM_CONFIG)) || (await loadCustomConfig());
 }
 
 /**