git: Remove JobStatus from PendingOp in favour of in-flight pruning (#42955)

The idea is that we only store running (`!self.finished`) or finished
(`self.finished`) pending ops, while everything else (skipped, errored)
jobs are pruned out immediately. We don't really need them in the grand
scheme of things anyway.

Release Notes:

- N/A

crates/git_ui/src/git_panel.rs

@@ -2662,7 +2662,7 @@ impl GitPanel {
                 && pending
                     .ops
                     .iter()
-                    .any(|op| op.git_status == pending_op::GitStatus::Reverted && op.finished())
+                    .any(|op| op.git_status == pending_op::GitStatus::Reverted && op.finished)
             {
                 continue;
             }