Reader - fix 0 at bottom of loading following stream.

[Addison-Stavlo]

Related to # #99427

Proposed Changes

• converts items.length in the rendering logic check to be a boolean value, so it doesn't drop a 0 in the page.

BEFORE

AFTER

Why are these changes being made?

• It was dropping a 0 in the page.

Testing Instructions

• Test the /reader feed and verify there is no longer a 0 at the bottom.
• You can use devtools to throttle network speed if needed, or you can adjust the forcePlaceholders value in the code
• Visit the bottom of your recent stream (or select an individual site under recent, but there must be some posts), and verify the footer still shows up after scrolling to the bottom of the feed.

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
  • For UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

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[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.

[DustyReagan]

This fixes the issue! Thanks for opening the PR!