[Wallet] Feature banner redesign

[TanyaEfremova]

Update styles of the feature banner on our Wallet page accordingly to the new design.

Description

• Change the size of the container dedicated for images (it can stretch all the way the right) to give more space for the images. This will help to bring in more balance.
• Add optional description field, which would allow to provide more info about the announcement.
• General style changes (backround, text color adjustments, minimize size of the banner)
• Change placement position (move under the 1st block)

Same changes may apply to other banners (e.g. on the Core page)
See example

Figma

Design

Screenshot