MM-59827: Remove user profile invalidations from channel APIs (#27720)

We were invalidating the userProfileByIds cache unnecessarily
when it wasn't really needed. It's just that the InvalidateCacheForUser
method wiped off all user related caches, when we just needed to wipe
user-channel related caches.

To fix this, we split the user cache invalidation method into two
and just call the InvalidateChannelCacheForUser method from app/channel.go.

https://mattermost.atlassian.net/browse/MM-59827
```release-note
NONE
```

server/channels/app/channel.go

@@ -288,7 +288,7 @@ func (a *App) CreateChannel(c request.CTX, channel *model.Channel, addMember boo
 			return nil, model.NewAppError("CreateChannel", "app.channel_member_history.log_join_event.internal_error", nil, "", http.StatusInternalServerError).Wrap(err)
 		}
 
-		a.InvalidateCacheForUser(channel.CreatorId)
+		a.Srv().Platform().InvalidateChannelCacheForUser(channel.CreatorId)
 	}
 
 	a.Srv().Go(func() {
@@ -372,8 +372,8 @@ func (a *App) getOrCreateDirectChannelWithUser(c request.CTX, user, otherUser *m
 }
 
 func (a *App) handleCreationEvent(c request.CTX, userID, otherUserID string, channel *model.Channel) {
-	a.InvalidateCacheForUser(userID)
-	a.InvalidateCacheForUser(otherUserID)
+	a.Srv().Platform().InvalidateChannelCacheForUser(userID)
+	a.Srv().Platform().InvalidateChannelCacheForUser(otherUserID)
 
 	a.Srv().Go(func() {
 		pluginContext := pluginContext(c)
@@ -499,7 +499,7 @@ func (a *App) CreateGroupChannel(c request.CTX, userIDs []string, creatorId stri
 
 	jsonIDs := model.ArrayToJSON(userIDs)
 	for _, userID := range userIDs {
-		a.InvalidateCacheForUser(userID)
+		a.Srv().Platform().InvalidateChannelCacheForUser(userID)
 
 		message := model.NewWebSocketEvent(model.WebsocketEventGroupAdded, "", channel.Id, userID, nil, "")
 		message.Add("teammate_ids", jsonIDs)
@@ -1294,7 +1294,7 @@ func (a *App) UpdateChannelMemberNotifyProps(c request.CTX, data map[string]stri
 		}
 	}
 
-	a.InvalidateCacheForUser(member.UserId)
+	a.Srv().Platform().InvalidateChannelCacheForUser(member.UserId)
 	a.invalidateCacheForChannelMembersNotifyProps(member.ChannelId)
 
 	// Notify the clients that the member notify props changed
@@ -1331,7 +1331,7 @@ func (a *App) PatchChannelMembersNotifyProps(c request.CTX, members []*model.Cha
 	}
 
 	for userId := range userIds {
-		a.InvalidateCacheForUser(userId)
+		a.Srv().Platform().InvalidateChannelCacheForUser(userId)
 	}
 	for channelId := range channelIds {
 		a.invalidateCacheForChannelMembersNotifyProps(channelId)
@@ -1375,7 +1375,7 @@ func (a *App) updateChannelMember(c request.CTX, member *model.ChannelMember) (*
 		}
 	}
 
-	a.InvalidateCacheForUser(member.UserId)
+	a.Srv().Platform().InvalidateChannelCacheForUser(member.UserId)
 
 	// Notify the clients that the member notify props changed
 	evt := model.NewWebSocketEvent(model.WebsocketEventChannelMemberUpdated, "", "", member.UserId, nil, "")
@@ -1568,7 +1568,7 @@ func (a *App) addUserToChannel(c request.CTX, user *model.User, channel *model.C
 		return nil, model.NewAppError("AddUserToChannel", "app.channel_member_history.log_join_event.internal_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
 	}
 
-	a.InvalidateCacheForUser(user.Id)
+	a.Srv().Platform().InvalidateChannelCacheForUser(user.Id)
 	a.invalidateCacheForChannelMembers(channel.Id)
 
 	return newMember, nil
@@ -2562,7 +2562,7 @@ func (a *App) removeUserFromChannel(c request.CTX, userIDToRemove string, remove
 		}
 	}
 
-	a.InvalidateCacheForUser(userIDToRemove)
+	a.Srv().Platform().InvalidateChannelCacheForUser(userIDToRemove)
 	a.invalidateCacheForChannelMembers(channel.Id)
 
 	var actorUser *model.User

server/channels/app/platform/web_hub.go

@@ -196,11 +196,15 @@ func (ps *PlatformService) InvalidateCacheForChannelPosts(channelID string) {
 }
 
 func (ps *PlatformService) InvalidateCacheForUser(userID string) {
+	ps.InvalidateChannelCacheForUser(userID)
+	ps.Store.User().InvalidateProfileCacheForUser(userID)
+}
+
+func (ps *PlatformService) InvalidateChannelCacheForUser(userID string) {
 	ps.Store.Channel().InvalidateAllChannelMembersForUser(userID)
 	ps.ClearUserSessionCache(userID)
 
 	ps.Store.User().InvalidateProfilesInChannelCacheByUser(userID)
-	ps.Store.User().InvalidateProfileCacheForUser(userID)
 }
 
 func (ps *PlatformService) InvalidateCacheForUserTeams(userID string) {