fix: remove cache fallback that allowed different app versions

The .haf_app_smart_cache_lookup template was searching for caches with
different app commits when AUTO_SKIP_SYNC was true. This caused schema
incompatibility issues when only CI config changed - the test would use
a cache from an older app version that was missing new schemas.

Now the cache lookup only uses exact key match (HAF_COMMIT + app commit)
or falls back to HAF-only cache and runs sync. This ensures schema
compatibility between sync and test jobs.