Refactor send_request in client.rs (#13701)

Closes #13687
Closes #13686

# Description
Light refactoring of `send_request `in `client.rs`. In the end there are
more lines but now the logic is more concise and facilitates adding new
conditions in the future. Unit tests ran fine and I tested a few cases
manually.
Cool project btw, I'll be using nushell from now on.

crates/nu-command/tests/commands/network/http/post.rs

@@ -133,6 +133,36 @@ fn http_post_json_list_is_success() {
     assert!(actual.out.is_empty())
 }
 
+#[test]
+fn http_post_json_int_is_success() {
+    let mut server = Server::new();
+
+    let mock = server.mock("POST", "/").match_body(r#"50"#).create();
+
+    let actual = nu!(format!(
+        r#"http post -t 'application/json' {url} 50"#,
+        url = server.url()
+    ));
+
+    mock.assert();
+    assert!(actual.out.is_empty())
+}
+
+#[test]
+fn http_post_json_string_is_success() {
+    let mut server = Server::new();
+
+    let mock = server.mock("POST", "/").match_body(r#""test""#).create();
+
+    let actual = nu!(format!(
+        r#"http post -t 'application/json' {url} "test""#,
+        url = server.url()
+    ));
+
+    mock.assert();
+    assert!(actual.out.is_empty())
+}
+
 #[test]
 fn http_post_follows_redirect() {
     let mut server = Server::new();