linux: Implement local time zone support (#14610)

I decided to remove the GPUI APIs since `chrono` already provides this
functionality, and is already been used for this purpose in other parts
of the code (e.g.
[here](80402a6840/crates/zed/src/main.rs (L756))
or
[here](80402a6840/crates/ui/src/utils/format_distance.rs (L258)))

These usages end up calling the `time_format` crate, which takes in a
`UtcOffset`. It's probably cleaner to rewrite the crate to take in
`chrono` types, but that would require rewriting most of the code there.

Release Notes:

- linux: Use local time zone in chat and Git blame

crates/collab_ui/Cargo.toml

@@ -32,6 +32,7 @@ test-support = [
 anyhow.workspace = true
 call.workspace = true
 channel.workspace = true
+chrono.workspace = true
 client.workspace = true
 collections.workspace = true
 db.workspace = true

crates/collab_ui/src/chat_panel.rs

@@ -111,6 +111,7 @@ impl ChatPanel {
                 this.is_scrolled_to_bottom = !event.is_scrolled;
             }));
 
+            let local_offset = chrono::Local::now().offset().local_minus_utc();
             let mut this = Self {
                 fs,
                 client,
@@ -120,7 +121,7 @@ impl ChatPanel {
                 active_chat: Default::default(),
                 pending_serialization: Task::ready(None),
                 message_editor: input_editor,
-                local_timezone: cx.local_timezone(),
+                local_timezone: UtcOffset::from_whole_seconds(local_offset).unwrap(),
                 subscriptions: Vec::new(),
                 is_scrolled_to_bottom: true,
                 active: false,

crates/collab_ui/src/notification_panel.rs

@@ -127,11 +127,12 @@ impl NotificationPanel {
                 },
             ));
 
+            let local_offset = chrono::Local::now().offset().local_minus_utc();
             let mut this = Self {
                 fs,
                 client,
                 user_store,
-                local_timezone: cx.local_timezone(),
+                local_timezone: UtcOffset::from_whole_seconds(local_offset).unwrap(),
                 channel_store: ChannelStore::global(cx),
                 notification_store: NotificationStore::global(cx),
                 notification_list,