Update CI config: remove core tests that break plugin routes on Redmi…

…ne 5.1.3

.github/workflows/5_1_3.yml

@@ -89,8 +89,7 @@ jobs:
       - name: Prepare Redmine source
         working-directory: redmine
         run: |
-          # TODO Remove the following line when https://www.redmine.org/issues/40551 is fixed
-          sed -i -e 's/.*mocha.*/  gem "mocha", "2.1.0"/' Gemfile # Fix core tests not compatible with Mocha 2.2.0
+          rm -f test/integration/routing/plugins_test.rb # Fix routing tests # TODO Remove this line when https://www.redmine.org/issues/38707 is fixed
           sed -i '/rubocop/d' Gemfile
           rm -f .rubocop*
           cp plugins/redmine_base_rspec/spec/support/database-${{ matrix.db }}.yml config/database.yml