Bug: symbolic links are not automatically overwritten when extracted from tar archive to File store

[Wwwsylvia]

Original issue in ORAS CLI repo: oras-project/oras#1593

Currently, when extracting a tar archive in File store, we do not handle the case where a symbolic link contained in the archive already exists in the file system. When such a case happens, a LinkError is thrown by the os.Symlink(target, path) function call on line 190.

oras-go/content/file/utils.go

Lines 187 to 191 in e4dc64e

	case tar.TypeSymlink:
	var target string
	if target, err = ensureLinkPath(dir, prefix, path, header.Linkname); err == nil {
	err = os.Symlink(target, path)
	}

Since we automatically overwrite other files by default, we should keep it consistent for symbolic links as well.