Fixed fetching messages for campaign replies

[alanhartless]

Please be sure you are submitting this against the staging branch.

Q	A
Bug fix?	Y
New feature?
Automated tests included?
Related user documentation PR URL
Related developer documentation PR URL
Issues addressed (#s or URLs)	#5793
BC breaks?
Deprecations?

Description:

The first time messages were fetched for campaign replies, the imap search "UNSEEN" was used. But subsequent calls used "UID n:*" where n is the UID of the last message processed. Turns out, PHP's implementation of imap_search does not support that criteria. This PR fixes this by using imap_fetch_overview for the UID criteria.

Steps to reproduce the bug:

1. Go to Mautic's Configuration -> Email Settings and setup an IMAP account for Campaign Replies under Monitored Inboxes
2. Create a campaign that sends an email with a replies to email decision attached. Add some action to the green anchor (tag, points, whatever).
3. Add a contact to the campaign
4. Reply to the email received from the campaign; be sure to send it to the email address configured as the monitored inbox and leave the body intact
5. If testing against a self hosted install, run the command php app/console mautic:emails:fetch. If testing in the cloud, jobs are ran every 2 minutes
6. The campaign decision is never acknowledged

Steps to test this PR:

1. Repeat and the campaign decision will be acknowledged

[LevryKurniawan]

That's perfect!

[luizeof]

@alanhartless Tested and it Works Perfectly with Gmail on 2.14.0

[Lalilu]

I've overwritten the two files of the fix (https://github.com/mautic/mautic/pull/6376/files/c124868b322b2f9bbc875d59376e8823d313c3ac#diff-917b16827cc7ddce112292c90eac2bd9) on my v2.14.0 instance. It didn't help. Still doesn't work.

CronJob log with v2.14.0:
0 emails processed for {myserver.com:993/imap/ssl}INBOX with a criteria of UID 2:*

With overwritten files:
0 emails processed for {myserver.com:993/imap/ssl}INBOX with a criteria of UID 3:1000000003

Did I do it right to test it?

[kuzmany]

Tested. Works for me.
4 approved reviews. We should merge it.

[kuzmany]

Any native speaker, please review our docs mautic/documentation#291

[papazetis]

I am using mailjet (i have tried amazon ses as well) as send service and gmail for inbox and it never worked.

[RehanNischal]

Is it solved yet??