[IMPROVE] Update system messages' behavior in rooms

[matheusbsilva137]

Proposed changes (including videos or screenshots)

• Update room's lastMessage when its "Hide System Messages" setting is updated;
• Display system messages in the last message field (in the sidebar, using the extended view) -- iff the system message sent is not hidden in the room;
• Send an alert to the room members when a system message is sent -- iff the system message sent is not hidden in the room;
• Properly update a room's lastMessage field when the previous lastMessage is deleted -- system messages can now be set as last messages.

Issue(s)

Task - ClickUp

Steps to test or reproduce

1. Go to Administration > Message > Hide System Messages and choose all the system messages you'd like to hide from all rooms;
2. Select a room in the sidebar and access Room Information > Edit > Hide System Messages, enable this setting and choose the system messages you'd like to be hidden in this room (additional to the ones chosen in the administration page);
3. Add or Remove a member from the room. If its corresponding system message is NOT hidden in the room, the room's last message will be updated (visible in the extended view mode sidebar) and an alert will be displayed to the other users in the room (it'll be moved up in the rooms list and its name will be in bold). Otherwise (if the message is not hidden in the room), it'll not be shown in the last message field and alerts won't be sent.

Further comments

The last message field (in the sidebar) displays the following message types (using i18n translation): uj (user joined), ul (user left), ut, livechat-close, livechat-started, room-archived, room-unarchived, room_e2e_enabled, room_e2e_disabled, au (user added), r (room name changed), ru (user removed), wm, user-muted, user-unmuted, subscription-role-added, subscription-role-removed.

[pierre-lehnen-rc]

The change is working as expect when the system message is hidden in the room level, but when hiding a sysetm message using the admin setting, the room's lastMessage is still displaying it.