feat: Add support for dialog tag and create example templates

[0yeifer]

New Dialog Block Templates Added
Two native <dialog> templates are now available:

1. Dialog Show:
   • Contains a trigger button with onclick="<dialogId>.showModal()"
   • Modal includes a simple form and three action buttons and one required text input:
     • Validate and Close (form submission via method="dialog" validating input required)
     • Non-Validate Close (submit without validation using attribute formnovalidate)
     • JS Close (native call to close() method via onclick="<dialogId>.close()")
   • Supports native features:
     • Esc key cancellation

2. Dialog Modal:
   • Open-by-default dialog (open attribute) with confirmation button
   • Demonstrates attribute-driven visibility

Key Implementation Notes:

• Zero external JS dependencies - uses native HTMLDialogElement methods via ID references
• Templates maintaining Frappe Builder low-code philosophy

Next Steps:
There is an editor/published view visibility discrepancy that remains unresolved due to the display handling.
Awaiting feedback, I will keep an eye on the PR for any necessary changes.

[0yeifer]

Hello @surajshetty3416 Is there any issue with this PR or something that needs to be changed/improved? I could work on any corrections if needed.

[surajshetty3416]

@0yeifer if you are still around, can you try and make this feature completely functional using this feature (it's almost at the final stage of review) by adding block level scripts?

[0yeifer]

Hi @surajshetty3416 , sure, I'll check it out 👀

[surajshetty3416]

@0yeifer, the feature is merged now... if you want to take a look.