Encrypted and unencrypted messages can be collapsed together

[BetaRays]

Describe the bug
When receiving an encrypted message right after an unencrypted message, they will both get collapsed because they are close together.
As the message encrypted indicator is shown on the user name line, this makes the first message appear encrypted.

To Reproduce
Steps to reproduce the behavior:

1. Send an unencrypted message
2. Send an encrypted message close to the previous one

Expected behavior
Converse.js should make clear which messages were sent encrypted or not.

Screenshots

Converse.js:

Gajim:

Environment (please complete the following information):

• Desktop or Mobile? Desktop
• Browser [e.g. Chrome, Firefox] Firefox
• Converse.js version [e.g. 4.2.0] v11.0.0 (unreleased)