Ensure settings are being adjusted via settings profile selector (#35382)

This PR just pins down the behavior of the settings profile selector by
checking a single setting, `buffer_font_size`, as options in the
selector are changed / selected.

Release Notes:

- N/A

Cargo.lock

@@ -14709,6 +14709,7 @@ dependencies = [
 name = "settings_profile_selector"
 version = "0.1.0"
 dependencies = [
+ "client",
  "editor",
  "fuzzy",
  "gpui",
@@ -14718,6 +14719,7 @@ dependencies = [
  "project",
  "serde_json",
  "settings",
+ "theme",
  "ui",
  "workspace",
  "workspace-hack",