[display] Avoid display issues with missing fields (#11251)

* [display] only raise completion items when in completion request

* Don't check interfaces during display requests

* Use dms_full_typing instead

src/syntax/grammar.mly

@@ -189,7 +189,7 @@ and parse_class_content doc meta flags n p1 s =
 	let tl = parse_constraint_params s in
 	let rec loop had_display p0 acc =
 		let check_display p1 =
-			if not had_display && !in_display_file && display_position#enclosed_in p1 then
+			if not had_display && !in_display_file && !display_mode = DMDefault && display_position#enclosed_in p1 then
 				syntax_completion (if List.mem HInterface n then SCInterfaceRelation else SCClassRelation) None (display_position#with_pos p1)
 		in
 		match s with parser

src/typing/typeloadCheck.ml

@@ -564,8 +564,10 @@ module Inheritance = struct
 					   purpose. However, we STILL have to delay the check because at the time pending is handled, the class
 					   is not built yet. See issue #10847. *)
 					pending := (fun () -> delay ctx PConnectField check_interfaces_or_delay) :: !pending
-				| _ ->
+				| _ when ctx.com.display.dms_full_typing ->
 					check_interfaces ctx c
+				| _ ->
+					()
 			in
 			if is_extends then begin
 				if c.cl_super <> None then raise_typing_error "Cannot extend several classes" p;