fix(imap): Ignore non existent mailboxes / no select for MYRIGHTS

[ChristophWurst]

Fixes #8534

Regression of #8449. The code

mail/lib/IMAP/FolderMapper.php

Lines 70 to 80 in 5055ba8

	try {
	$client->status($mailbox["mailbox"]);
	} catch (Horde_Imap_Client_Exception $e) {
	// ignore folders which cause errors on access
	// (i.e. server-side system I/O errors)
	if (in_array($e->getCode(), [
	Horde_Imap_Client_Exception::UNSPECIFIED,
	], true)) {
	return null;
	}
	}

was dropped, which previously caught access to invalid mailboxes and silently ignored the mailbox.

Mailbox synchronization fails if a nonexistent mailbox is access during the MYRIGHTS command, if the server supports ACLs.

C: 4 LIST () "" (*) RETURN (SUBSCRIBED SPECIAL-USE)
S: * LIST (\Subscribed \Archive) "/" Archives
S: * LIST (\Subscribed \Drafts) "/" Drafts
S: * LIST (\Subscribed \Sent) "/" Sent
S: * LIST (\Subscribed \Trash) "/" Trash
S: * LIST (\NonExistent) "/" shared
S: * LIST (\Subscribed) "/" shared/[email protected]
S: * LIST (\Subscribed) "/" INBOX

but then

C: 11 MYRIGHTS shared
>> ERROR: read/timeout error.
>> ERROR: Server closed the connection.

[ChristophWurst]

This patch can be tested with the bitgrid test accounts

[ChristophWurst]

/backport to stable2.2

[ChristophWurst]

/backport to stable3.2

[kesselb]

Do we need the same logic for \NoSelect?
Found a bug report for Thunderbird https://bugzilla.mozilla.org/show_bug.cgi?id=222394

[ChristophWurst]

That probably makes sense. Let me add that too.

[hamza221]

Tested creating new mailbox doesn't work on main and works with these fixes

[st3iny]

Wasn't able to reproduce the initial problem but the code looks good.

[backportbot-nextcloud]

The backport to stable2.2 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable2.2
git pull origin stable2.2

# Create the new backport branch
git checkout -b fix/foo-stable2.2

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable2.2

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport