chore: remove root user restriction in RepoCache rebuild

1. Removed the check that prevented root users from writing to
states.json during cache rebuild
2. The previous workaround was needed when ll-cli could make states.json
owned by root, causing permission issues
3. This restriction is no longer necessary as the underlying ownership
issue has been addressed
4. Root users can now fully rebuild the repository cache without
skipping the write operation

Log: Root users can now rebuild the repository cache and persist changes
to states.json

Influence:
1. Test RepoCache rebuild functionality when running as root user
2. Verify states.json is correctly written and readable by both root and
non-root users
3. Test cache rebuild in scenarios where ll-cli initializes the
repository as root
4. Verify file ownership and permissions of states.json after root-
initiated rebuilds
5. Test cache persistence across multiple rebuild operations as root
6. Verify no permission denied errors occur during cache writes as root

Author: dengbo11

libs/linglong/src/linglong/repo/repo_cache.cpp

@@ -117,12 +117,6 @@ utils::error::Result<void> RepoCache::rebuild(const api::types::v1::RepoConfigV2
         this->cache.layers.emplace_back(std::move(item));
     }
 
-    // FIXME: ll-cli may initialize repo, it can make states.json own by root
-    if (getuid() == 0) {
-        LogE("Rebuild the cache by root, skip to write data to states.json");
-        return LINGLONG_OK;
-    }
-
     auto ret = writeToDisk();
     if (!ret) {
         return LINGLONG_ERR(ret);