git: Pass project environment to git binary invocations (#26301)

Closes #26213 

Release Notes:

- Git Beta: pass down environment variables from project to git
operations

crates/remote_server/src/headless_project.rs

@@ -87,10 +87,12 @@ impl HeadlessProject {
             buffer_store
         });
 
+        let environment = project::ProjectEnvironment::new(&worktree_store, None, cx);
         let git_store = cx.new(|cx| {
             GitStore::new(
                 &worktree_store,
                 buffer_store.clone(),
+                Some(environment.clone()),
                 session.clone().into(),
                 None,
                 cx,
@@ -105,7 +107,6 @@ impl HeadlessProject {
                 cx,
             )
         });
-        let environment = project::ProjectEnvironment::new(&worktree_store, None, cx);
         let toolchain_store = cx.new(|cx| {
             ToolchainStore::local(
                 languages.clone(),