Feature: add Campaign Cover Block

[JoshuaHungDinh]

Resolves GIVE-1505 / GIVE-1973

Description

• Removes references of video support on the media Uploader from the campaign settings and creation modal.
  Slack conversation reference: https://lw.slack.com/archives/C04SLRDD9CK/p1738173558503109
• Improved styles on the Uploader components.
• Adds Campaign Cover Block to the block editor. This block's image can only be updated from the campaign settings. A placeholder will be displayed if no image is set from the campaign settings. The image supports alignment, resizing & duotone.

Affects

Campaign settings & Campaign Cover Block

Visuals

https://www.loom.com/share/b168317f31ef40ba9a3a1add7cea7b81?sid=70ad126a-bde3-476a-8b0f-31e9b76d5773

Testing Instructions

• Add the campaign cover block without an image, verify a placeholder is displayed.
• Add the campaign cover block with an image verify the image is can be resized, aligned and supports duotone. These blocks settings need to be verified on both the frontend page & in the admin editor.
• Verify the UI/UX does not imply that videos can be supported from the block uploader.

Pre-review Checklist

• Acceptance criteria satisfied and marked in related issue
• Self Review of code and UX completed

[alaca]

Good job, @JoshuaHungDinh 👍

[rickalday]

Passed manual tests!