chore: Unset Redis config after spec (#8685)

The sentinel configuration set in this specification seems to be affecting other specifications. So, let's ensure that the memoised config variable gets unset after execution of the spec.

spec/lib/redis/config_spec.rb

@@ -42,6 +42,11 @@ describe Redis::Config do
       end
     end
 
+    after do
+      # ensuring the redis config is unset and won't affect other tests
+      described_class.instance_variable_set(:@config, nil)
+    end
+
     it 'checks for app redis config' do
       expect(described_class.app.keys).to contain_exactly(:url, :password, :sentinels, :timeout, :reconnect_attempts, :ssl_params)
       expect(described_class.app[:url]).to eq("redis://#{redis_master_name}")
@@ -59,6 +64,11 @@ describe Redis::Config do
         end
       end
 
+      after do
+        # ensuring the redis config is unset and won't affect other tests
+        described_class.instance_variable_set(:@config, nil)
+      end
+
       it 'checks for app redis config and sentinel passwords will be empty' do
         expect(described_class.app.keys).to contain_exactly(:url, :password, :sentinels, :timeout, :reconnect_attempts, :ssl_params)
         expect(described_class.app[:url]).to eq("redis://#{redis_master_name}")
@@ -77,6 +87,11 @@ describe Redis::Config do
         end
       end
 
+      after do
+        # ensuring the redis config is unset and won't affect other tests
+        described_class.instance_variable_set(:@config, nil)
+      end
+
       it 'checks for app redis config and redis password is replaced in sentinel config' do
         expect(described_class.app.keys).to contain_exactly(:url, :password, :sentinels, :timeout, :reconnect_attempts, :ssl_params)
         expect(described_class.app[:url]).to eq("redis://#{redis_master_name}")