Extend an existing Views filter (NumericFilter) throws exception
So, yeah I ended up investigating more and more and I needed to specify a config schema definition as it follows.

# @file config/schema/foobar.views.schema.yml
#
# Schema for the views plugins.

views.filter.project_size_range_select:
  type: views_filter
  label: 'Foobar numeric'

views.filter_value.project_size_range_select:
  type: views.filter_value.numeric
  label: 'Foobar Numeric'


The full gist is available here if anyone is interested.