[CoreAttachWindow] Fix window UI
[CoreAttachWindow] Fix window UI

- Add caption to the local tab ('Path to the dump file')
- make the local path field adjustable to the window size
(before: https://screenshot.googleplex.com/7p3QKthas6rQh6m;
after: https://screenshot.googleplex.com/9wVPuuWVSkxH6JX)
- show error messages in red to make them stand out more.
GitOrigin-RevId: 3f6b586f08c81882f2bbfa7479ec9434423c397e

googlestadia/vsi-lldb,googlestadia/vsi-lldb,googlestadia/vsi-lldb