[MM-12476] Consistent paging arguments limit/offset vs page/perPage for plugin API (#9838)

* Change GetTeamMembers() and GetPublicChannelsForTeam() arguments to page, perPage for plugin API

* Add test for GetPublicChannelsForTeam()

* Add test for GetTeamMembers()

* Changes as requested

* Change return from GetPublicChannelsForTeam() to []*model.Channel

plugin/api.go

@@ -139,7 +139,7 @@ type API interface {
 	DeleteTeamMember(teamId, userId, requestorId string) *model.AppError
 
 	// GetTeamMembers returns the memberships of a specific team.
-	GetTeamMembers(teamId string, offset, limit int) ([]*model.TeamMember, *model.AppError)
+	GetTeamMembers(teamId string, page, perPage int) ([]*model.TeamMember, *model.AppError)
 
 	// GetTeamMember returns a specific membership.
 	GetTeamMember(teamId, userId string) (*model.TeamMember, *model.AppError)
@@ -154,7 +154,7 @@ type API interface {
 	DeleteChannel(channelId string) *model.AppError
 
 	// GetPublicChannelsForTeam gets a list of all channels.
-	GetPublicChannelsForTeam(teamId string, offset, limit int) (*model.ChannelList, *model.AppError)
+	GetPublicChannelsForTeam(teamId string, page, perPage int) ([]*model.Channel, *model.AppError)
 
 	// GetChannel gets a channel.
 	GetChannel(channelId string) (*model.Channel, *model.AppError)