Hotfix: Emoji Picker button hover misalignment fix

What does this MR do and why?

Fixes a regression caused by a recent migration: Emoji picker: Migrate dropdown to GlDisclosureD... (!142201 - merged)

Emoji Picker button fixes:

• Fixes hover misalignment
• Fixes active Emoji (shows smile Emoji when active)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Go to an issuable and check the Emoji picker for comments

Realated to #430246 (closed), !142834 (merged), !142201 (merged)