Tests: Remove defunct config: time_zone_aware_types

We started setting this config in rails 5, to preserve the behavior
in rails 4, ie. `time` columns being "zone-unaware".

If we rewrite our `time` column tests to focus on the time only
(and not the date) then we don't need to set time_zone_aware_types.

spec/dummy_app/config/application.rb

@@ -18,7 +18,6 @@ module Dummy
     config.active_support.escape_html_entities_in_json = true
     config.active_support.test_order = :sorted
     config.secret_key_base = "A fox regularly kicked the screaming pile of biscuits."
-    config.active_record.time_zone_aware_types = [:datetime]
 
     # In rails >= 6.0, "`.represent_boolean_as_integer=` is now always true,
     # so setting this is deprecated and will be removed in Rails 6.1."

spec/paper_trail/model_spec.rb

@@ -335,8 +335,9 @@ RSpec.describe(::PaperTrail, versioning: true) do
       expect(previous_widget.a_datetime.to_time.utc.to_i).to(eq(t0.to_time.utc.to_i))
     end
 
-    it "handle times" do
-      expect(previous_widget.a_time.utc.to_i).to(eq(t0.utc.to_i))
+    it "handle times (time only, no date)" do
+      format = ->(t) { t.utc.strftime "%H:%M:%S" }
+      expect(format[previous_widget.a_time]).to eq(format[t0])
     end
 
     it "handle dates" do
@@ -362,7 +363,8 @@ RSpec.describe(::PaperTrail, versioning: true) do
         assert_in_delta(153.01, reified.a_float, 0.001)
         assert_in_delta(2.7183, reified.a_decimal, 0.0001)
         expect(reified.a_datetime.to_time.utc.to_i).to(eq(t0.to_time.utc.to_i))
-        expect(reified.a_time.utc.to_i).to(eq(t0.utc.to_i))
+        format = ->(t) { t.utc.strftime "%H:%M:%S" }
+        expect(format[reified.a_time]).to eq(format[t0])
         expect(reified.a_date).to(eq(d0))
         expect(reified.a_boolean).to(be_truthy)
       end