Do not show last visited repos if there is less than 4 in total

[zc-devs]

Clear and concise description of the problem

It doesn't make much sense to duplicate the repositories in the last visited block too, if there are <=4 in total

Besides, odd number of items look not so smooth.

Suggested solution

Do not display last visited block if there are only four repositories

Alternative

Use repos pinning

Additional context

Woodpecker next-9f0611d1a1, Gitea 1.22.4, Postgres 16

Validations

• Checked that the feature isn't part of the next version already [https://woodpecker-ci.org/faq#which-version-of-woodpecker-should-i-use]
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.