Add instructions for safely replacing certificates in Certificate Man…

[GabrielAzion]

…ager

Related issue: EDU-6622

The "Replacing a certificate safely" section has been added to all four Certificate Manager reference pages:

Files modified:

1. src/content/docs/en/pages/main-menu/reference/build/edge-application/digital-certificates.mdx — EN Build reference
2. src/content/docs/pt-br/pages/menu-principal/referencia/build/edge-application/digital-certificates.mdx — PT-BR Build reference
3. src/content/docs/en/pages/main-menu/reference/secure/edge-firewall/digital-certificates.mdx — EN Secure/Firewall reference
4. src/content/docs/pt-br/pages/menu-principal/referencia/secure/edge-firewall/digital-certificates.mdx — PT-BR Secure/Firewall reference

What was added:

Each file received a new top-level section positioned after the "Trusted CA certificate" subsection and before the "Let's Encrypt certificate" section. The section includes:

• A brief intro explaining zero-downtime replacement and the ~5-minute propagation time
• An 8-step numbered procedure covering upload → naming → domain association → save
• A :::tip callout reinforcing the pre-expiration upload strategy (the core customer pain point)
• A :::note callout clarifying that the old certificate entry persists and can be deleted after validation

Editorial decisions:

• Placeholder names used (yourdomain.com, seudominio.com) instead of real customer names, as requested
• Propagation time stated as "approximately 5 minutes" matching the support team's guidance
• Steps cover both Domains and Workloads UI paths since accounts may use either
• Tone is direct and task-oriented, consistent with Azion's brand voice guidelines