🚧 Feedback modal UI 🚧 (#3536)

[[PR Description]]

TODO: 
- [x] Add placeholder text to editor
- [x] Add external link icon to "Community repo" button
- [x] Show `not-allowed` cursor for disabled buttons
- [ ] Add `Headline` ui component
- [ ] Finish UI pass
- [ ] Fix `IconPosition` on button (should swap the icon side)
- [ ] Add conditional tooltip for disabled "Send feedback" button.
- [ ] Add common/top feedback link.
- [ ] Add `vw`/`vh` units to allow sizing the modal based on viewport
size.

Release Notes:

- N/A

crates/ui2/src/components/icon.rs

@@ -51,6 +51,7 @@ pub enum Icon {
     CopilotDisabled,
     Dash,
     Envelope,
+    ExternalLink,
     ExclamationTriangle,
     Exit,
     File,
@@ -123,13 +124,13 @@ impl Icon {
             Icon::Close => "icons/x.svg",
             Icon::Collab => "icons/user_group_16.svg",
             Icon::Copilot => "icons/copilot.svg",
-
             Icon::CopilotInit => "icons/copilot_init.svg",
             Icon::CopilotError => "icons/copilot_error.svg",
             Icon::CopilotDisabled => "icons/copilot_disabled.svg",
             Icon::Dash => "icons/dash.svg",
             Icon::Envelope => "icons/feedback.svg",
             Icon::ExclamationTriangle => "icons/warning.svg",
+            Icon::ExternalLink => "icons/external_link.svg",
             Icon::Exit => "icons/exit.svg",
             Icon::File => "icons/file.svg",
             Icon::FileDoc => "icons/file_icons/book.svg",