Enable clippy::needless_update (#8830)

This PR enables the
[`clippy::needless_update`](https://rust-lang.github.io/rust-clippy/master/index.html#/needless_update)
rule and fixes the outstanding violations.

Release Notes:

- N/A

crates/collab/src/tests/integration_tests.rs

@@ -3885,7 +3885,6 @@ async fn test_collaborating_with_diagnostics(
                 DiagnosticSummary {
                     error_count: 1,
                     warning_count: 0,
-                    ..Default::default()
                 },
             )]
         )
@@ -3922,7 +3921,6 @@ async fn test_collaborating_with_diagnostics(
             DiagnosticSummary {
                 error_count: 1,
                 warning_count: 0,
-                ..Default::default()
             },
         )]
     );