extensions_ui: Add ability to filter extensions by category (#27005)

This PR adds the ability to filter the list of extensions by category:


https://github.com/user-attachments/assets/ea7b518e-4769-4e2e-8bbe-e75f9f01edf9

Release Notes:

- Added the ability to filter the list of extensions by category.

Cargo.lock

@@ -4821,7 +4821,6 @@ dependencies = [
  "db",
  "editor",
  "extension_host",
- "feature_flags",
  "fs",
  "fuzzy",
  "gpui",
@@ -4834,6 +4833,7 @@ dependencies = [
  "serde",
  "settings",
  "smallvec",
+ "strum",
  "telemetry",
  "theme",
  "ui",