fixing diagram page links in sidebar

General MR

Summary

Fixing broken links in the bb docs sidebar, found under Understanding Big Bang > Architecture Diagrams

Relevant logs/screenshots

'Metrics Data Flow' and 'Network Encryption and Ingress' currently point to non-existent markdown files, returning Padawan 404 Page not found errors. Looks like the correct markdown files are there, their filenames just end in -diagram .

Linked Issue

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Upgrade Notices

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