Add support for `IMG` tags with `fetchpriority=low` or `fetchpriority=auto` #33209

Job	Run time
Determine Matrix	4s
Multisite Default / Test before	1m 14s
Single Site Default / Test before	1m 14s
Multisite Memcached / Test before	1m 14s
Multisite Default / Test current	1m 14s
Single Site Memcached / Test current	1m 14s
Single Site Default / Test current	1m 13s
Single Site Memcached / Test before	1m 14s
Multisite Memcached / Test current	1m 14s
Failed workflow tasks	1s
Slack Notifications	-1s
matrix.label	-1s
	9m 54s

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