Groups are created blocked if 1:1 chat is blocked

[link2xt]

Since #4316 is merged and got into 1.113.0 if 1:1 chat with the contact is blocked, groups that it create are also blocked and are not just contact requests.

However, I think this change should have checked if the contact is blocked rather than if 1:1 chat with the contact is blocked. 1:1 chat being blocked does not mean that the user blocked the contact, it also happens when the user scans a group QR code with unknown inviter and 1:1 chat with the inviter is blocked to hide it:

deltachat-core-rust/src/securejoin/bob.rs

Lines 33 to 42 in 4d74f62

	// A 1:1 chat is needed to send messages to Alice. When joining a group this chat is
	// hidden, if a user starts sending messages in it it will be unhidden in
	// receive_imf.
	let hidden = match invite {
	QrInvite::Contact { .. } => Blocked::Not,
	QrInvite::Group { .. } => Blocked::Yes,
	};
	let chat_id = ChatId::create_for_contact_with_blocked(context, invite.contact_id(), hidden)
	.await
	.with_context(|| format!("can't create chat for contact {}", invite.contact_id()))?;

This has caused problems with running mailadm tests. There, bot admin joins an administration group via the QR code. This results in creation of two chats with the bot: blocked 1:1 chat and unblocked group chat. Group chat joined via the QR code is explicitly created as unblocked:

deltachat-core-rust/src/securejoin/bob.rs

Line 190 in 4d74f62

Blocked::Not,

Then outside user writes a message to the bot and the bot relays this message to the new support group named "[email protected] support group" where it adds all admins (only one in the test). But the admin has 1:1 chat with the bot blocked and this triggers blocking of the support group as well.

This issue prevented us from upgrading mailadm to versions of the core >=1.113.0: deltachat/mailadm#126 (comment) But not upgrading only helps the tests to pass, while in reality if admins use core >=1.113.0 they may not see the support group at all.

cc @Hocuri

[link2xt]

Made a fix with a test at #4691