Add git: open modified files action (#32347)

Ported over a vscode/cursor command that I like using : )

Release Notes:

- Added "open modified files" command

crates/git/src/git.rs

@@ -57,6 +57,7 @@ actions!(
         ExpandCommitEditor,
         GenerateCommitMessage,
         Init,
+        OpenModifiedFiles,
     ]
 );