refactor: improve loading state management in Events and Groups pages

[Tharunraja7]

Fix Events empty state glitch & loading consistency

Repro Steps:

• Go to Home page → click on Events section and observe loading
• Notice the brief "No events found matching your criteria" flicker

Fix:

• Aligned Events loading logic with Groups page pattern to avoid premature empty state rendering
• Removed redundant spinner from Groups page (skeleton already handles loading)

Impact:

• Eliminates UI flicker on Events page
• Improves loading consistency across Events and Groups

please let me know if any changes need

[tompscanlan]

LGTM, thanks @Tharunraja7