feat: Implement toast to promote channels

[sandrade-dcl]

What does this PR change?

In order to show the new Channels feature to players, we have implemented this toast:

Also, a "new" label appears now on top of the channels header inside the conversations panel:

Acceptance Criteria

• Toast can be dismissed with a close icon
• Opening the chat icon will close the toast
• Toast will still appear in the next session until the player dismiss it
• After dissmiss, it wont appear anymore for that user.
• This toast is enabled via feature flag (promote_channels_toast)

How to test the changes?

https://play.decentraland.zone/?renderer-branch=feat/promote-channels-toast

Our Code Review Standards

https://github.com/decentraland/unity-renderer/blob/master/docs/code-review-standards.md

[github-actions[bot]]

After the CI passes:

• This branch can be previewed at https://play.decentraland.zone/?renderer-branch=feat/promote-channels-toast
• Code coverage report: https://renderer-artifacts.decentraland.org/branch-coverage/feat/promote-channels-toast
• Benchmark report: https://renderer-artifacts.decentraland.org/branch-benchmark/feat/promote-channels-toast/index.html

[RominaMarchetti]

@sandrade-dcl here goes my comments.

1- Adjust the pixels per unit in the close button container that looks too rounded. 2- Idem for the [new] label. This also applies for the label in the channels separator. 3- Tooltip background must be white. Currently looks light grey. 4- Reduce the gap between the tooltip and the social tab a half. 5- Aligned the tooltip with the social tab on the left.

[sandrade-dcl]

@sandrade-dcl here goes my comments.

1- Adjust the pixels per unit in the close button container that looks too rounded. 2- Idem for the [new] label. This also applies for the label in the channels separator. 3- Tooltip background must be white. Currently looks light grey. 4- Reduce the gap between the tooltip and the social tab a half. 5- Aligned the tooltip with the social tab on the left.

@RominaMarchetti I already applied your requested changes. Only one thing: about the point 5 ("Aligned the tooltip with the social tab on the left"), I think it looks worse now because the bottom arrow doesn't coincide with the chat button in the taskbar:

I think it is happening because the taskbar drawed in Figma is a bit different to the real one. In my opinion it looks better if we move the toast a bit to the left. Something like this:

If we want to make the toast margin coincide with the taskbar one we should modify the toast image to move the arrow a bit to the left, or modify the taskbar in order to make it coincide with figma.

[RominaMarchetti]

Got it @sandrade-dcl 👍