P2-1057 Fix breadcrumb for static posts page

[herregroen]

Context

• Prevents stripping the final breadcrumb for the static posts page as this page does not have a page crumb.

Summary

This PR can be summarized in the following changelog entry:

• Fixes a bug where the last breadcrumb item was stripped in breadcrumb Schema output on subsequent pages of a static posts page.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Set a static posts page.
• Go to the second page of it.
• The second breadcrumb item should be present.

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

• Breadcrumbs schema generation.

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Documentation

• I have written documentation for this change.

Quality assurance

• I have tested this code to the best of my abilities
• I have added unittests to verify the code works as intended

Fixes #

[increddibelly]

after this PR, Breadcrumb schema is as seen in screenshot.