Replace isahc with async ureq (#18414)

REplace isahc with ureq everywhere gpui is used.

This should allow us to make http requests without libssl; and avoid a
long-tail of panics caused by ishac.

Release Notes:

- (potentially breaking change) updated our http client

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Co-authored-by: Mikayla <mikayla@zed.dev>

crates/extension_cli/Cargo.toml

@@ -18,7 +18,7 @@ clap = { workspace = true, features = ["derive"] }
 env_logger.workspace = true
 extension = { workspace = true, features = ["no-webrtc"] }
 fs.workspace = true
-isahc_http_client.workspace = true
+reqwest_client.workspace = true
 language.workspace = true
 log.workspace = true
 rpc.workspace = true