PLOTTER add null option for facet

[XsirdanielX]

When facet is selected in PLOTTER, there is no way to go back. Add a null option to allow going back to one plot.

Example: http://dorresteintesthub.ucsd.edu:6549/?gnps_tall_table_usi=mzdata%3AGNPS%3ATASK-ce85da1063a741d9a2febf08d62d4daf-feature_statistics%2Fdata_long.csv&gnps_quant_table_usi=&gnps_metadata_table_usi=&feature=5&metadata=ATTRIBUTE_Combined_Sample_Location&facet=ATTRIBUTE_Sample_Type&groups=SSA_BF_Air%3BSSA_IB_Air%3BSSA_SS_Air%3BSSA_SIO_Air%3BDOM_BF_SZ%3BDOM_IB_SZ%3BDOM_IB_OW%3BDOM_SS_SZ%3BDOM_SIO_SZ%3BDOM_SIO_OW%3BDOM_Holl_RW&plot_type=box&color=&points_toggle=False&theme=ggplot2&animation_column=&lat_column=None&long_column=None&map_animation_column=&map_scope=world