fix: Correct activeBehavior for the cases of multiple CSS classes

[webJose]

No description provided.

[Copilot]

Pull Request Overview

This pull request fixes a bug in the activeBehavior function where multiple CSS classes were not being handled correctly. The fix ensures that when clsx returns a string with multiple space-separated classes, they are properly split and added individually to the element's classList.

Key changes:

• Modified class handling to split space-separated class strings and filter out empty values
• Updated classList operations to use spread operator for adding/removing multiple classes
• Added comprehensive test coverage for different class input types (string, object, array)

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/lib/behaviors/active.svelte.ts	Fixed class handling to properly split and manage multiple CSS classes
src/lib/behaviors/active.svelte.test.ts	Added test cases for different class input formats and updated existing assertions

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