i3943: don't send left_anchor field through the advanced_parser

The blacklight advanced search gem was being overly helpful,
noticing that there were a set of parentheses in the query:

  Washington post (Washington, D.C. : 1877)

And accordingly, it parsed it into the following nested
query, which caused a Solr error:

  _query_:"{!edismax }Washington post" AND _query_:"{!edismax }Washington, D.C. : 1877"*

app/controllers/catalog_controller.rb

@@ -549,6 +549,7 @@ class CatalogController < ApplicationController
         qf: '$left_anchor_qf',
         pf: '$left_anchor_pf'
       }
+      field.advanced_parse = false
     end
 
     config.add_search_field('publisher') do |field|

spec/requests/catalog_spec.rb

@@ -14,6 +14,12 @@
     expect(response.status).to eq(200)
   end
 
+  it 'can handle parentheses in the left_anchor field' do
+    get '/?search_field=left_anchor&q=Washington+post+(Washington%2C+D.C.+%3A+1877)'
+
+    expect(response.status).to eq(200)
+  end
+
   context "BadRequest when clicking back to search" do
     # This url produces ActionController::BadRequest
     let(:url) do