doc: sequence diagram image asset is missing/broken

Please also confirm the following

• I have searched the main issue tracker of NeMo Guardrails repository and believe that this is not a duplicate

Issue Kind

Improving documentation

Existing Link

https://docs.nvidia.com/nemo/guardrails/reference/guardrails-sequence-diagrams

Description

Summary

The sequence diagram on the Guardrails Sequence Diagrams documentation page is missing or failing to load. Instead of rendering the visual diagram, the page only displays the raw alt fallback text.

Affected Page

• URL: https://docs.nvidia.com/nemo/guardrails/reference/guardrails-sequence-diagrams

Steps to Reproduce

1. Navigate to the Guardrails Sequence Diagrams documentation page.
2. Scroll to the section under "The following diagram depicts the guardrails process in detail:".

Expected Behavior

A rendered sequence diagram image/graphic illustrating the complete NeMo Guardrails lifecycle (Input Validation, Dialog, and Output Validation stages).

Actual Behavior

The image asset does not load, and the text block description of the diagram (Sequence diagram showing the complete guardrails process in NeMo Guardrails...) is displayed directly on the page instead.