Reconfigure Renovate PR check fails to create PR comment

[rarkins]

Describe the proposed change(s).

On GitHub, Renovate fails to find the PR associated with the renovate/reconfigure branch, because the author is not Renovate Bot and we retrieve only PRs by Renovate's username.

Same problem may occur on other platforms too.

We probably don't want to fetch all PRs by every author, although maybe we need to fetch all open PRs plus all closed ones by Renovate. Alternatively maybe there's a way to efficiently find just one (open) PR for a particular branch?

Related discussion: #25721

[RahulGautamSingh]

It is possible to look for PRs open from a particluar branch using Gitlab and Github API but Gitea still has no such support (related issue)

[rarkins]

Shouldn't be necessary. For Gitea we already fetch every single PR and then do filtering by author on the client side:

renovate/lib/modules/platform/gitea/index.ts

Lines 111 to 113 in 8de2126

	if (createdBy && botUserName && createdBy !== botUserName) {
	return null;
	}

Therefore it's possible to save the whole list and/or specifically the reconfigure branch.