fix(typescript-estree): do not call export of clearProgramCache (#6540)

Do not call export of clearProgramCache

Calling it exports `undefined` instead of making it an alias of
`clearCaches`, which I believe was the intent.

packages/typescript-estree/src/clear-caches.ts

@@ -18,4 +18,4 @@ export function clearCaches(): void {
 }
 
 // TODO - delete this in next major
-export const clearProgramCache = clearCaches();
+export const clearProgramCache = clearCaches;