Keep thousands separator in record and site counts

[sanketio]

Fixes #1477.

total_items_i18n and the network admin site count formatted an already-separated number with %d, truncating it at the first comma — 1,501 items rendered as 1 items. Switched both to %s, matching WP_List_Table::pagination(). The network count has no test because is_network_admin() reads a constant the suite cannot set per-test.

Checklist

• Project documentation has been updated to reflect the changes in this pull request, if applicable.
• I have tested the changes in the local development environment (see contributing.md).
• I have added phpunit tests.

Release Changelog

• Fix: Keep the thousands separator in the records table item count and the network admin site count.

[PatelUtkarsh]

@sanketio Thanks for PR!

Can you update pr desc with template as per https://github.com/xwp/stream/blob/develop/.github/PULL_REQUEST_TEMPLATE.md?

[sanketio]

Updated the description to use the template.

[PatelUtkarsh]

That was quick; Can you write Haiku for this PR changes in comment?