DEV: Remove full group refreshes from tests (#25414)

We have all these calls to Group.refresh_automatic_groups! littered throughout the tests. Including tests that are seemingly unrelated to groups. This is because automatic group memberships aren't fabricated when making a vanilla user. There are two places where you'd want to use this:

You have fabricated a user that needs a certain trust level (which is now based on group membership.)
You need the system user to have a certain trust level.
In the first case, we can pass refresh_auto_groups: true to the fabricator instead. This is a more lightweight operation that only considers a single user, instead of all users in all groups.

The second case is no longer a thing after #25400.

spec/lib/post_creator_spec.rb

@@ -1081,7 +1081,6 @@ RSpec.describe PostCreator do
     fab!(:target_user2) { Fabricate(:moderator) }
     fab!(:unrelated_user) { Fabricate(:user) }
     let(:post) do
-      Group.refresh_automatic_groups!
       PostCreator.create!(
         user,
         title: "hi there welcome to my topic",
@@ -1097,8 +1096,7 @@ RSpec.describe PostCreator do
       SiteSetting.min_first_post_length = 20
       SiteSetting.min_post_length = 25
       SiteSetting.body_min_entropy = 20
-      user.update!(trust_level: 3)
-      Group.refresh_automatic_groups!
+      user.change_trust_level!(TrustLevel[3])
 
       expect {
         PostCreator.create!(
@@ -1198,13 +1196,12 @@ RSpec.describe PostCreator do
     end
 
     it "does not increase posts count for small actions" do
-      topic = Fabricate(:private_message_topic, user: Fabricate(:user))
+      topic = Fabricate(:private_message_topic, user: Fabricate(:user, refresh_auto_groups: true))
 
       Fabricate(:post, topic: topic)
 
       1.upto(3) do |i|
         user = Fabricate(:user)
-        Group.refresh_automatic_groups!
         topic.invite(topic.user, user.username)
         topic.reload
         expect(topic.posts_count).to eq(1)
@@ -1235,7 +1232,6 @@ RSpec.describe PostCreator do
     end
 
     it "works as expected" do
-      Group.refresh_automatic_groups!
       # Invalid archetype
       creator = PostCreator.new(user, base_args)
       creator.create
@@ -1324,7 +1320,6 @@ RSpec.describe PostCreator do
     end
     fab!(:unrelated) { Fabricate(:user) }
     let(:post) do
-      Group.refresh_automatic_groups!
       PostCreator.create!(
         user,
         title: "hi there welcome to my topic",