slurmrestd - Set type for http_context_t->request

Void pointer no longer required as request_t is fully defined.

Issue: 50189
diff --git a/src/slurmrestd/http.c b/src/slurmrestd/http.c
index 929db25..6bd7b77 100644
--- a/src/slurmrestd/http.c
+++ b/src/slurmrestd/http.c
@@ -108,7 +108,7 @@
 	/* http parser plugin state */
 	http_parser_state_t *parser;
 	/* http request_t */
-	void *request;
+	request_t *request;
 } http_context_t;
 
 /* default keep_alive value which appears to be implementation specific */