Move link to the last item in formatting toolbar

What does this MR do and why?

In the content editor's formatting toolbar, move the link option as the last item. As per the suggestion in !91574 (comment 1013366642)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Open any wiki page
2. If content editor isn't already active, click "Edit rich text" to activate it.
3. Enter some text, and select some of it to activate the formatting toolbar.
4. Notice that the link icon is the last item in the toolbar now.

MR acceptance checklist

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