Customizations: Adjust search bar height in layout methods for consistency across widgets

[joshspicer]

No description provided.

[Copilot]

Pull request overview

Adjusts the AI Customization management list widgets’ layout calculations so the search row height is treated consistently across the different list widgets, aligning the UI sizing behavior.

Changes:

• Updated list widget layout() calculations to use a 52px fallback search row height when offsetHeight is not available.
• Changed the search/button row styling from margin to padding so the row’s spacing is included in its measured height.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/vs/workbench/contrib/chat/browser/aiCustomization/pluginListWidget.ts	Updates layout fallback used when computing available list height under the search/button row.
src/vs/workbench/contrib/chat/browser/aiCustomization/mcpListWidget.ts	Updates layout fallback used when computing available list height under the search/button row.
src/vs/workbench/contrib/chat/browser/aiCustomization/aiCustomizationListWidget.ts	Updates layout fallback used when computing available list height under the search/button row.
src/vs/workbench/contrib/chat/browser/aiCustomization/media/aiCustomizationManagement.css	Replaces margin with padding on the search/button row so spacing contributes to measured element height.