Feat: Add tooltip displaying users who reacted with a particular emoji

[abirc8010]

Brief Title

This PR introduces a tooltip displaying users who reacted with a specific emoji.

Acceptance Criteria fulfillment

• Added state hoveredReaction to track the currently hovered reaction.
• Created a tooltipMap to store the tooltip content for each reaction.
• Implemented getTooltipContent to generate a string of users who reacted,
• For each reaction, the tooltip is displayed on hover and shows the users who reacted, with a limit of 9 users before summarizing with "and {remainingNumberOfReactions} other(s)".
• Added relevant styling to the tooltip for proper alignment

Fixes #819

Video/Screenshots

Screencast.from.2025-01-06.22-44-53.webm

PR Test Details

Note: The PR will be ready for live testing at https://rocketchat.github.io/EmbeddedChat/pulls/pr-820 after approval. Contributors are requested to replace <pr_number> with the actual PR number.