TWAS/cTWAS codes needs to support dropping event patterns

[gaow]

Currently impelmented as :

# remove no effect sQTL cluster specific contexts
          if (any(grepl("no_effect_sQTL", twas_weights_results[[gene_db]]$data_type))){

which is very specific. We should be using a more general regex to screen any patterns in the context names to ignore.