[MM-37772] Idiomatic naming (URL, URI, API) (#18128)

* s/Url/URL/g & s/Uri/URI/g

* s/Api/API/g

api4/user_viewmembers_test.go

@@ -11,7 +11,7 @@ import (
 	"github.com/mattermost/mattermost-server/v6/model"
 )
 
-func TestApiResctrictedViewMembers(t *testing.T) {
+func TestAPIResctrictedViewMembers(t *testing.T) {
 	th := Setup(t)
 	defer th.TearDown()