Fix non-standard whitespace

[trepmal]

There are a couple non-standard whitespace characters in the body of one of core's emails:

The WordPress team is willing to help you. Forward this email to %s and the team will work with you to make sure your site is working.

The characters appear in "the team will" - though I expect that here and in the diff they won't render..

[SergeyBiryukov]

In 28956:

Remove non-breaking spaces from auto update email text.

props trepmal.
fixes #28715.