Don't whitelist events for all filter

What does this MR do?

• Add Issue events tab to the events filter in the activity feeds
• Make sure the All tab actually includes all activity
• Make the All tab selected by default

Are there points in the code the reviewer needs to double check?

It's quite a straightforward implementation, so I don't think so, but I'm not familiar with the codebase.

Why was this MR needed?

See #24826 (closed).

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated (I don't think this is relevant here)
• API support added (not relevant)
• Tests added for this feature/bug
• All builds are passing (I suppose so)
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

#24826 (closed)