MM-2954 - Add a separate post type for /me messages and update formatting (#11082)

* MM-2954

* Added new const post type for /me commands
* Modified me command to return response text without *__* wrapper
* Modified unit test for MeCommand to reflect changes
* Added unit test for the me command provider

* * Reverted change to text property in me command response
* Added original message in me command response props
* Updated unit tests

* gofmt changes

api4/commands_test.go

@@ -350,9 +350,16 @@ func TestMeCommand(t *testing.T) {
 	if len(p1.Order) != 2 {
 		t.Fatal("Command failed to send")
 	} else {
-		if p1.Posts[p1.Order[0]].Message != `*hello*` {
-			t.Log(p1.Posts[p1.Order[0]].Message)
-			t.Fatal("invalid shrug response")
+		pt := p1.Posts[p1.Order[0]].Type
+		if pt != model.POST_ME {
+			t.Log(pt)
+			t.Fatalf("invalid post type, got '%s', wanted '%s'", pt, model.POST_ME)
+		}
+		msg := p1.Posts[p1.Order[0]].Message
+		want := "*hello*"
+		if msg != want {
+			t.Log(msg)
+			t.Fatalf("invalid me response message, got '%s', wanted '%s'", msg, want)
 		}
 	}
 }