Show upvoter emails in Suggestion admin panel

[Stitipragyanbarik]

Description

Added a read-only field in the Suggestion admin panel to display the list of users who have upvoted each suggestion.
Displays the username and email of each upvoter.
Shows “No upvotes yet.” if no users have upvoted.
Helps admins quickly see who supported each suggestion.
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Rationale

Currently, the Suggestion admin panel does not provide visibility into which users have upvoted suggestions.
This change allows admins to track upvotes and improves transparency and moderation capabilities.

(Why is this change required? What problem does it solve?)

Phabricator Ticket

https://phabricator.wikimedia.org/T381682

(Link to the Phabricator ticket)

How Has This Been Tested?

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Types of changes

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Minor change (fix a typo, add a translation tag, add section to README, etc.)

[Stitipragyanbarik]

@Samwalton9 can you check?

[Samwalton9]

One of the team's software developers will review this soon :)