feat(dialog): implement critical variant

[AykutSarac]

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.

[github-actions]

🎉 This PR is included in version 3.0.0-beta.21 🎉

The release is available on:

• npm package (@beta dist-tag)
• GitHub release

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