[pseudoIDs] Fixes for room alias tests (#3159)

Some (deceptively) simple fixes for some bugs that caused room alias
tests to fail (sytext `tests/30rooms/05aliases.pl`). Each commit has
details about what it fixes.

Sytest results:

- Sytest before (79d4a0e):
https://gist.github.com/swedgwood/972ac4ef93edd130d3db0930703d6c82
- Sytest after (4b09bed):
https://gist.github.com/swedgwood/504b00ac4ee892acb757b7fac55fa28a

Room aliases go from `8/15` to `15/15`, but looks like these fixes also
managed to fix about `4` other tests, which is a nice bonus :)

Signed-off-by: `Sam Wedgwood <sam@wedgwood.dev>`

roomserver/api/alias.go

@@ -16,26 +16,8 @@ package api
 
 import (
 	"regexp"
-
-	"github.com/matrix-org/gomatrixserverlib/spec"
 )
 
-// SetRoomAliasRequest is a request to SetRoomAlias
-type SetRoomAliasRequest struct {
-	// ID of the user setting the alias
-	UserID string `json:"user_id"`
-	// New alias for the room
-	Alias string `json:"alias"`
-	// The room ID the alias is referring to
-	RoomID string `json:"room_id"`
-}
-
-// SetRoomAliasResponse is a response to SetRoomAlias
-type SetRoomAliasResponse struct {
-	// Does the alias already refer to a room?
-	AliasExists bool `json:"alias_exists"`
-}
-
 // GetRoomIDForAliasRequest is a request to GetRoomIDForAlias
 type GetRoomIDForAliasRequest struct {
 	// Alias we want to lookup
@@ -63,22 +45,6 @@ type GetAliasesForRoomIDResponse struct {
 	Aliases []string `json:"aliases"`
 }
 
-// RemoveRoomAliasRequest is a request to RemoveRoomAlias
-type RemoveRoomAliasRequest struct {
-	// ID of the user removing the alias
-	SenderID spec.SenderID `json:"user_id"`
-	// The room alias to remove
-	Alias string `json:"alias"`
-}
-
-// RemoveRoomAliasResponse is a response to RemoveRoomAlias
-type RemoveRoomAliasResponse struct {
-	// Did the alias exist before?
-	Found bool `json:"found"`
-	// Did we remove it?
-	Removed bool `json:"removed"`
-}
-
 type AliasEvent struct {
 	Alias      string   `json:"alias"`
 	AltAliases []string `json:"alt_aliases"`