cargo: Bump rustc to 1.89 (#36818)

Update Rustc to 1.89.

Reviewable by commit.

Leftover work:
- #37330 
- #38777

---------

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
Co-authored-by: sagudev <16504129+sagudev@users.noreply.github.com>

components/net/indexeddb/engines/sqlite/database_model.rs

@@ -12,6 +12,7 @@ pub enum Column {
     Version,
 }
 
+#[allow(dead_code)]
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Model {
     pub name: String,

components/net/indexeddb/engines/sqlite/object_store_index_model.rs

@@ -14,6 +14,7 @@ pub enum Column {
     MultiEntryIndex,
 }
 
+#[allow(dead_code)]
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Model {
     pub id: i32,