Show extension download counts with thousands separators (#12857)

This PR adjusts the extension download counts to be displayed using
thousands separators.

Release Notes:

- Adjusted extension download counts to display with thousands
separators (e.g., `1,000,000`).

crates/extensions_ui/Cargo.toml

@@ -24,6 +24,7 @@ fs.workspace = true
 fuzzy.workspace = true
 gpui.workspace = true
 language.workspace = true
+num-format.workspace = true
 picker.workspace = true
 project.workspace = true
 release_channel.workspace = true

crates/extensions_ui/src/extensions_ui.rs

@@ -16,6 +16,7 @@ use gpui::{
     InteractiveElement, KeyContext, ParentElement, Render, Styled, Task, TextStyle,
     UniformListScrollHandle, View, ViewContext, VisualContext, WeakView, WhiteSpace, WindowContext,
 };
+use num_format::{Locale, ToFormattedString};
 use release_channel::ReleaseChannel;
 use settings::Settings;
 use std::ops::DerefMut;
@@ -487,8 +488,11 @@ impl ExtensionsPage {
                         .size(LabelSize::Small),
                     )
                     .child(
-                        Label::new(format!("Downloads: {}", extension.download_count))
-                            .size(LabelSize::Small),
+                        Label::new(format!(
+                            "Downloads: {}",
+                            extension.download_count.to_formatted_string(&Locale::en)
+                        ))
+                        .size(LabelSize::Small),
                     ),
             )
             .child(