Drop ORDER BY clause from copy step of image data refresh when adding a limit

[krysal]

Description

The recent image data refresh in the dev environment failed the copy step. We realized that turning on a limit to the number of rows copied (done in WordPress/openverse-infrastructure#908) was also applying an ordering clause, which is prohibitive for a table with so many rows (+700 million).

We still want a subset of the production data in dev and really don't need it to be pseudo-random so we can drop this piece of the clause generation and just let it select a limit:

openverse/ingestion_server/ingestion_server/queries.py

Lines 185 to 190 in cf5778a

	# The audioset view does not have identifiers associated with it
	if upstream_table != "audioset_view":
	select_insert += d(
	"""
	ORDER BY identifier"""
	)

Additional context

Related to #736, WordPress/openverse-api#474 (original PR adding the clause) and #3912 (because it's necessary for testing in staging).