Primary cache: do not err on PrimaryNotFound

[teh-cmc]

Ignore PrimaryNotFound errors on the cached entity_iterator path, the same way the vanilla path does.

• Fixes Primary cache: fix error log sometimes when scrolling out of bounds #4858
• DNR: requires Primary caching 19 (final): de-staticify cache globals #4856

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[github-actions]

Size changes

Name	cmc/primcache_19_statification	4892/merge	Change
JS	139.41 kiB	111.52 kiB	-20.01%