Add support for insert_text_mode of a completion (#28171)

I wanted this for CONL (https://conl.dev )'s nascent langauge server,
and it seems like most of the support was already wired up on the LSP
side, so this surfaces it into the editor.

Release Notes:

- Added support for the `insert_text_mode` field of completions from the
language server protocol.

crates/debugger_ui/src/session/running/console.rs

@@ -367,6 +367,7 @@ impl ConsoleQueryBarCompletionProvider {
                             documentation: None,
                             confirm: None,
                             source: project::CompletionSource::Custom,
+                            insert_text_mode: None,
                         })
                     })
                     .collect(),
@@ -409,6 +410,7 @@ impl ConsoleQueryBarCompletionProvider {
                         documentation: None,
                         confirm: None,
                         source: project::CompletionSource::Custom,
+                        insert_text_mode: None,
                     })
                     .collect(),
             ))