feat(dialog): implement critical variant

Related to #853

Implements critical dialog functionality to prevent closing and hides the close button for critical dialogs.

Adds a critical property to bl-dialog to mark dialogs as critical, which disables closing through keyboard, backdrop, and close button interactions.
Conditionally renders the close button in the dialog header based on the critical property, effectively hiding it for critical dialogs.
Updates event handling to prevent closing critical dialogs through escape key presses and outside clicks.
Includes a new story in bl-dialog.stories.ts to demonstrate a critical dialog with the critical property set to true.
Adds tests in bl-dialog.test.ts to verify that critical dialogs cannot be closed through keyboard, backdrop, and close button interactions, and to ensure the close button is hidden for critical dialogs.

Trendyol / baklava