🧹 chore: Remove Unused Cache Configuration Keys (#9551)

* Remove unused STATIC_CONFIG and LIBRECHAT_YAML_CONFIG cache keys.

These cache keys were identified as dead code - they were being written to but never read from anywhere in the codebase after a recent refactor:

- STATIC_CONFIG was used as a cache namespace that stored configuration data
- LIBRECHAT_YAML_CONFIG was the key used within that namespace to store parsed YAML config
- The cache.set() operation in loadCustomConfig.js stored the config but no cache.get() operations retrieved it
- Configuration data is already handled through other mechanisms without caching

* # removed tests regarding cache

packages/data-provider/src/config.ts

@@ -1219,14 +1219,6 @@ export enum CacheKeys {
    * Key for accessing the model token config cache.
    */
   TOKEN_CONFIG = 'TOKEN_CONFIG',
-  /**
-   * Key for the librechat yaml config cache.
-   */
-  LIBRECHAT_YAML_CONFIG = 'LIBRECHAT_YAML_CONFIG',
-  /**
-   * Key for the static config namespace.
-   */
-  STATIC_CONFIG = 'STATIC_CONFIG',
   /**
    * Key for the app config namespace.
    */