Improve mark-seen-logic

[rottabonus]

What has changed?

• When message is only fully visible on the viewport for 1s, then we mark it as unseen.
• If fetching older messages for buddy or initial messages, and we receive a response where the oldest message is unseen, keep fetching until
  a) received oldest message is not unread
  b) received all messages

Bonus:
User-report e2e-test was broken, so at the same time when fixed, I added a fix for this: https://trello.com/c/zYeyhfCO/936-keyboardavoider-to-user-report-form

Why was the change made?

When investigating messaging issues reported by users, found out this oversight.

1. Message is always marked as read if the message is opened in the list (even if not visible!)
2. The unseen-selector of buddy-messages checks only the last received message, but its possible that user has only seen most recent unread messages, but has not scrolled to top

Caveats?

• Dangerous to touch this logic, but tested it pretty well

Related Trello issue

Link to the Trello ticket

Checklist

• I have updated relevant documentation in READMES

[pheis]

What happens here?

Why we do nothing if len is less than max messages at once?

[rottabonus]

If there is under that many messages, we dont want to fetch older messages.
There can only be older messages if there is more than the fetch amount.

[pheis]

Taa ei oo mulle ilmiselvaa et taa on oikein mut salee on :D, jos oot varma et menee oikein ni sit fine!

Must tuntu et tas on joku edge case mut ei kyl valtsiin oo

[pheis]

Probably proper good

I did not get why we do nothing if len is less than 10 with messages gottten on UI layer.

To me that feels more like API related decision that should not be done on rendering layer. There is not enough context to understand WHY on the UI code part.

I would like to understand WHY we do that check?

LGTM otherwise