fix(keyboard-trap): fixed a server rendering bug

[agliga]

There is a bug when you import keyboard trap on the server that it breaks.
This is because the observer is globally defined.
It should only break if you call "trap" on the server.
Added a check to only initialize the observer if window is defined.

[Copilot]

Pull Request Overview

This PR fixes a server-side rendering bug in the keyboard trap component where importing the module would break on the server due to a globally defined MutationObserver. The fix adds a window check to conditionally initialize the observer only in browser environments.

• Added conditional initialization of the MutationObserver based on window availability
• Updated observer usage to handle null cases with optional chaining
• Moved observer declaration to the top of the file for better organization

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