Remove feature flag

config/feature_flags/development/dynamic_nonce_creation.yml

----
-name: dynamic_nonce_creation
-introduced_by_url:
-rollout_issue_url:
-milestone: '13.9'
-type: development
-group: group::manage
-default_enabled: false

spec/lib/gitlab/crypto_helper_spec.rb

@@ -32,10 +32,6 @@ RSpec.describe Gitlab::CryptoHelper do
   end
 
   describe '.aes256_gcm_decrypt' do
-    before do
-      stub_feature_flags(dynamic_nonce_creation: false)
-    end
-
     context 'when token was encrypted using static nonce' do
       let(:encrypted) { described_class.aes256_gcm_encrypt('some-value', nonce: described_class::AES256_GCM_IV_STATIC) }
 
@@ -54,18 +50,6 @@ RSpec.describe Gitlab::CryptoHelper do
       it 'does not save hashed token with iv value in database' do
         expect { described_class.aes256_gcm_decrypt(encrypted) }.not_to change { TokenWithIv.count }
       end
-
-      context 'with feature flag switched on' do
-        before do
-          stub_feature_flags(dynamic_nonce_creation: true)
-        end
-
-        it 'correctly decrypts encrypted string' do
-          decrypted = described_class.aes256_gcm_decrypt(encrypted)
-
-          expect(decrypted).to eq 'some-value'
-        end
-      end
     end
   end
 end

spec/models/concerns/token_authenticatable_strategies/encrypted_spec.rb

@@ -68,10 +68,6 @@ RSpec.describe TokenAuthenticatableStrategies::Encrypted do
     context 'when using optional strategy' do
       let(:options) { { encrypted: :optional } }
 
-      before do
-        stub_feature_flags(dynamic_nonce_creation: false)
-      end
-
       it 'returns decrypted token when an encrypted token is present' do
         allow(instance).to receive(:read_attribute)
           .with('some_field_encrypted')