Bug: multiselect dots in plotly plot caused an error

Multi-select dots in plotly plot caused this error:


[link](https://foraging-behavior-browser.allenneuraldynamics-test.org/?if_load_bpod_sessions=False&filter_subject_id=&filter_session=1.0&filter_session=55.0&filter_finished_trials=0.0&filter_finished_trials=947.0&filter_foraging_eff=0.0&filter_foraging_eff=1.3475873305423873&filter_task=Uncoupled+Baiting&filter_task=Uncoupled+Without+Baiting&filter_task=Coupled+Baiting&filter_task=Coupled+Without+Baiting&table_height=300&tab_id=tab_session_x_y&x_y_plot_xname=session&x_y_plot_yname=session_run_time_in_min&x_y_plot_group_by=data_source&x_y_plot_if_show_dots=True&x_y_plot_if_aggr_each_group=True&x_y_plot_aggr_method_group=lowess&x_y_plot_if_aggr_all=True&x_y_plot_aggr_method_all=mean+%2B%2F-+sem&x_y_plot_smooth_factor=5&x_y_plot_if_use_x_quantile_group=False&x_y_plot_q_quantiles_group=20&x_y_plot_if_use_x_quantile_all=False&x_y_plot_q_quantiles_all=20&x_y_plot_if_show_diagonal=False&x_y_plot_dot_size=10&x_y_plot_dot_opacity=0.3&x_y_plot_line_width=2.0&x_y_plot_figure_width=1300&x_y_plot_figure_height=900&x_y_plot_font_size_scale=1.0&x_y_plot_selected_color_map=Plotly&x_y_plot_size_mapper=None&x_y_plot_size_mapper_gamma=1.0&x_y_plot_size_mapper_range=3&x_y_plot_size_mapper_range=20&session_plot_mode=sessions+selected+from+table+or+plot&auto_training_history_x_axis=date&auto_training_history_sort_by=subject_id&auto_training_history_sort_order=descending&auto_training_curriculum_name=Uncoupled+Baiting&auto_training_curriculum_version=1.0&auto_training_curriculum_schema_version=1.0)