file(ARCHIVE_EXTRACT): Fix resource leaks on error paths

extract_tar() allocates archive_read, archive_write_disk, and
archive_match handles, but several early-return error paths did not free
them. Most notably, a PATTERNS entry matching nothing leaked all three
handles on every call, which accumulates inside a long-running
configure.

Scope the three handles with std::unique_ptr custom deleters so every
return path releases them automatically.  std::unique_ptr does not
invoke the deleter for a null pointer, and the libarchive *_free
functions are themselves no-ops on null, so no explicit guarding is
required.  archive_read_free()/archive_write_free() implicitly close the
handle if needed, matching the previous behavior.

Fixes: #27872