Format Dashboard URL as Markdown link in PHP upgrade guide

[Copilot]

Bare URL in the PHP upgrade steps replaced with a proper Markdown link, consistent with how the Altis Dashboard is referenced elsewhere in the docs.

Change:

-1. Log in to the Altis Dashboard:
-   https://dashboard.altis-dxp.com/
+1. Log in to the [Altis Dashboard](https://dashboard.altis-dxp.com/).

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For Altis Team Use

Completion Checklist

Does this PR meet our definition of done? See the Play Book Definition of Done

• Has the acceptance criteria been met?
• Is the documentation updated (including README)?
• Do any code/documentation changes meet project standards?
• Are automatic tests in place to verify the fix or new functionality?
  • OR, are manual tests documented (at least on the ticket/PR)?
• Are any Playbook/Handbook pages updated?
• Has a new module release (patch/minor) been created/scheduled?
• Have the appropriate backport labels been added to the PR?
• Is there a roll-out (and roll-back) plan, if required?

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