Unify common styles of domains and sites screens to avoid having repeated styles in multiple places

[Imran92]

The sites management and the new revamped domain management pages have a lot of styles in common. During development, there are chances of styles being repeated.

As a cleanup during our cooldown, we'll try to unify the common styles.

[github-actions]

OpenAI suggested the following labels for this issue:

• [Feature Group] Appearance & Themes: The issue pertains to unifying common styles, which directly relates to the appearance of the management pages.
• [Feature] Global Styles: The suggested cleanup focuses on standardizing styles, aligning with the concept of global styles in the site editor.
• [Feature] Domain Management: The mention of domain management pages implies that this specific functionality is being affected by the style unification process.