MMCTL: Add import delete cmd for removing the import files (#29764)

Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>

server/cmd/mmctl/client/client.go

@@ -128,6 +128,7 @@ type Client interface {
 	GetUploadsForUser(ctx context.Context, userID string) ([]*model.UploadSession, *model.Response, error)
 	UploadData(ctx context.Context, uploadID string, data io.Reader) (*model.FileInfo, *model.Response, error)
 	ListImports(ctx context.Context) ([]string, *model.Response, error)
+	DeleteImport(ctx context.Context, name string) (*model.Response, error)
 	GetJob(ctx context.Context, id string) (*model.Job, *model.Response, error)
 	GetJobs(ctx context.Context, jobType string, status string, page int, perPage int) ([]*model.Job, *model.Response, error)
 	GetJobsByType(ctx context.Context, jobType string, page int, perPage int) ([]*model.Job, *model.Response, error)