[Agent] Rename the User-Agent string from Beats Agent to Elastic Agent (

#17765)

* Rename the User-Agent string from Beats Agent to Elastic Agent

When we changed the name of the agent to Elastic Agent we forgot to
update the User-Agent string send on every request.

x-pack/elastic-agent/CHANGELOG.asciidoc

@@ -18,11 +18,11 @@
 - Fixed merge of config {pull}17399[17399]
 - Handle abs paths on windows correctly {pull}17461[17461]
 - Improved cancellation of agent {pull}17318[17318]
+- Rename the User-Agent string from Beats Agent to Elastic Agent. {pull}17765[17765]
 - Fix issues when running `mage package` for all the platforms. {pull}17767[17767]
 - Remove the kbn-version on each request to the Kibana API. {pull}17764[17764]
 - Fixed process spawning on Windows {pull}17751[17751]
 
-
 ==== New features
 
 - Generate index name in a format type-dataset-namespace {pull}16903[16903]

x-pack/elastic-agent/pkg/fleetapi/client_test.go

@@ -76,14 +76,14 @@ func TestHTTPClient(t *testing.T) {
 		},
 	))
 
-	t.Run("Fleet user agent", withServer(
+	t.Run("Elastic Agent User-Agent string", withServer(
 		func(t *testing.T) *http.ServeMux {
 			msg := `{ message: "hello" }`
 			mux := http.NewServeMux()
 			mux.HandleFunc("/echo-hello", func(w http.ResponseWriter, r *http.Request) {
 				w.WriteHeader(http.StatusOK)
 				fmt.Fprintf(w, msg)
-				require.Equal(t, r.Header.Get("User-Agent"), "Beat Agent v8.0.0")
+				require.Equal(t, r.Header.Get("User-Agent"), "Elastic Agent v8.0.0")
 			})
 			return mux
 		}, func(t *testing.T, host string) {

x-pack/elastic-agent/pkg/fleetapi/round_trippers.go

@@ -28,7 +28,7 @@ func (r *FleetUserAgentRoundTripper) RoundTrip(req *http.Request) (*http.Respons
 // NewFleetUserAgentRoundTripper returns a  FleetUserAgentRoundTripper that actually wrap the
 // existing UserAgentRoundTripper with a specific string.
 func NewFleetUserAgentRoundTripper(wrapped http.RoundTripper, version string) http.RoundTripper {
-	const name = "Beat Agent"
+	const name = "Elastic Agent"
 	return &FleetUserAgentRoundTripper{
 		rt: kibana.NewUserAgentRoundTripper(wrapped, name+" v"+version),
 	}