Allow task context providers to access project env (#17964)

Closes #13106

Release Notes:

- Task context providers now have access to the local shell environment,
allowing local rust tool installations to work

Before:
<img width="1136" alt="Screenshot 2024-09-17 at 22 09 38"
src="https://github.com/user-attachments/assets/7d6c5606-4820-4f6f-92d1-c3d314b9ab42">

After:
<img width="1136" alt="Screenshot 2024-09-17 at 22 09 58"
src="https://github.com/user-attachments/assets/a962e607-15f5-44ce-b53e-a0dbe135f2d8">

crates/project/src/task_inventory.rs

@@ -8,7 +8,7 @@ use std::{
 };
 
 use anyhow::Result;
-use collections::{btree_map, BTreeMap, VecDeque};
+use collections::{btree_map, BTreeMap, HashMap, VecDeque};
 use futures::{
     channel::mpsc::{unbounded, UnboundedSender},
     StreamExt,
@@ -543,6 +543,7 @@ impl ContextProvider for BasicContextProvider {
         &self,
         _: &TaskVariables,
         location: &Location,
+        _: Option<&HashMap<String, String>>,
         cx: &mut AppContext,
     ) -> Result<TaskVariables> {
         let buffer = location.buffer.read(cx);