Backport of Fix audit-log encoding issue (CC-7337) into release/1.18.x (#20749)

Fix audit-log encoding issue (CC-7337) (#20345)

* add changes

* added changelog

* change update

* CE chnages

* Removed gzip size fix

* fix changelog

* Update .changelog/20345.txt



* Adding comments

---------

Co-authored-by: Ashesh Vidyut <134911583+absolutelightning@users.noreply.github.com>
Co-authored-by: Abhishek Sahu <abhishek.sahu@hashicorp.com>
Co-authored-by: Hans Hasselberg <hans@hashicorp.com>
Co-authored-by: srahul3 <rahulsharma@hashicorp.com>

.changelog/20345.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+  audit-logs: **(Enterprise Only)** Fixes non ASCII characters in audit logs because of gzip.
+```

agent/http.go

@@ -188,7 +188,9 @@ func (s *HTTPHandlers) handler() http.Handler {
 		// Register the wrapper.
 		wrapper := func(resp http.ResponseWriter, req *http.Request) {
 			start := time.Now()
-			handler(resp, req)
+
+			// this method is implemented by different flavours of consul e.g. oss, ce. ent.
+			s.enterpriseRequest(resp, req, handler)
 
 			labels := []metrics.Label{{Name: "method", Value: req.Method}, {Name: "path", Value: path_label}}
 			metrics.MeasureSinceWithLabels([]string{"api", "http"}, start, labels)
@@ -313,7 +315,6 @@ func (s *HTTPHandlers) handler() http.Handler {
 		h = mux
 	}
 
-	h = s.enterpriseHandler(h)
 	h = withRemoteAddrHandler(h)
 	s.h = &wrappedMux{
 		mux:     mux,

agent/http_ce.go

@@ -95,9 +95,9 @@ func parseACLAuthMethodEnterpriseMeta(req *http.Request, _ *structs.ACLAuthMetho
 	return nil
 }
 
-// enterpriseHandler is a noop for the enterprise implementation. we pass the original back
-func (s *HTTPHandlers) enterpriseHandler(next http.Handler) http.Handler {
-	return next
+func (s *HTTPHandlers) enterpriseRequest(w http.ResponseWriter, req *http.Request, handler func(http.ResponseWriter, *http.Request)) {
+	// no special handling for CE. Calling the default handler with default params.
+	handler(w, req)
 }
 
 // uiTemplateDataTransform returns an optional uiserver.UIDataTransform to allow