Stop leaking isahc assumption (#18408)

Users of our http_client crate knew they were interacting with isahc as
they set its extensions on the request. This change adds our own
equivalents for their APIs in preparation for changing the default http
client.

Release Notes:

- N/A

crates/zed/src/reliability.rs

@@ -4,8 +4,7 @@ use chrono::Utc;
 use client::telemetry;
 use db::kvp::KEY_VALUE_STORE;
 use gpui::{AppContext, SemanticVersion};
-use http_client::Method;
-use isahc::config::Configurable;
+use http_client::{HttpRequestExt, Method};
 
 use http_client::{self, HttpClient, HttpClientWithUrl};
 use paths::{crashes_dir, crashes_retired_dir};
@@ -491,7 +490,7 @@ async fn upload_previous_crashes(
                 .context("error reading crash file")?;
 
             let mut request = http_client::Request::post(&crash_report_url.to_string())
-                .redirect_policy(isahc::config::RedirectPolicy::Follow)
+                .follow_redirects(http_client::RedirectPolicy::FollowAll)
                 .header("Content-Type", "text/plain");
 
             if let Some((panicked_on, payload)) = most_recent_panic.as_ref() {