Removing noisy and always failing jobs

[janosdebugs]

This PR removes the almost always failing action that verifies if an issue is linked. It also removes the reminder to the PR assignee, since we don't follow that process anymore.

Target Release

1.8, 1.7, 1.6

[github-actions[bot]]

Reminder for the PR assignee: If this is a user-visible change, please update the changelog as part of the PR.

[github-actions[bot]]

Please link the relevant issue that this PR handles using one of the following words

• close | closes | closed | fix | fixes | fixed | resolve | resolves | resolved if the Pull Request resolves the issue - more details can be found here
• relates to | related to | part of if the Pull Request is just part of the solution

[ollevche]

Why do we want to remove the linked issues check? Shouldn't we link PRs in 99% of cases?

I also agree with @Evi1Pumpkin about the CHANGELOG check. However, we could add an "if" to not send a reminder if the CHANGELOG file is already edited.

[ghost]

Regarding linked issues, out of the last 20 merged PRs 4 had linked issues.