vsx: update extension information in the extension-editor

[kaiyue0329]

Fixes: #7434

What it does

• update styling for the action items in the extension header

How to test

• Click View in the top menu and select Extensions
• Search for an extension (ex. Bracket Pair Colorizer)
• The styling for the action items should look similar to how they look in vscode:
  

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[vince-fugnitto]

The changes look great! 👍

With the changes we now have:

• better spacing between subtitle items
• better font-weight (closer to vscode), making it more readable
• subtitle items are center-aligned and more consistent

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[Anasshahidd21]

I tried testing it. Looks good! Pretty similar as to how its done in vscode.
The padding looks decent and the menu-items no more looks too close to one another.