Use unix pipe to capture environment variables (#32136)

The use of `NamedTempFile` in #31799 was not secure and could
potentially cause write permission issues (see [this
comment](https://github.com/zed-industries/zed/issues/29528#issuecomment-2939672433)).
Therefore, it has been replaced with a Unix pipe.

Release Notes:
- N/A

crates/util/src/util.rs

@@ -315,7 +315,7 @@ pub fn load_login_shell_environment() -> Result<()> {
     // into shell's `cd` command (and hooks) to manipulate env.
     // We do this so that we get the env a user would have when spawning a shell
     // in home directory.
-    for (name, value) in shell_env::capture(Some(paths::home_dir()))? {
+    for (name, value) in shell_env::capture(paths::home_dir())? {
         unsafe { env::set_var(&name, &value) };
     }