Fix Rails/SaveBang Rubocop offenses for deployment modules

Contributes to https://gitlab.com/gitlab-org/gitlab/-/merge_requests/57644

.rubocop_manual_todo.yml

@@ -336,9 +336,6 @@ Rails/SaveBang:
     - 'spec/models/commit_spec.rb'
     - 'spec/models/commit_status_spec.rb'
     - 'spec/models/container_repository_spec.rb'
-    - 'spec/models/deploy_keys_project_spec.rb'
-    - 'spec/models/deploy_token_spec.rb'
-    - 'spec/models/deployment_spec.rb'
     - 'spec/models/design_management/version_spec.rb'
     - 'spec/models/diff_discussion_spec.rb'
     - 'spec/models/diff_note_spec.rb'

spec/models/deploy_keys_project_spec.rb

@@ -26,7 +26,7 @@ RSpec.describe DeployKeysProject do
         end
 
         it "doesn't destroy the deploy key" do
-          subject.destroy
+          subject.destroy!
 
           expect { deploy_key.reload }.not_to raise_error
         end
@@ -34,7 +34,7 @@ RSpec.describe DeployKeysProject do
 
       context "when the deploy key is private" do
         it "destroys the deploy key" do
-          subject.destroy
+          subject.destroy!
 
           expect { deploy_key.reload }.to raise_error(ActiveRecord::RecordNotFound)
         end
@@ -49,7 +49,7 @@ RSpec.describe DeployKeysProject do
       end
 
       it "doesn't destroy the deploy key" do
-        subject.destroy
+        subject.destroy!
 
         expect { deploy_key.reload }.not_to raise_error
       end

spec/models/deploy_token_spec.rb

@@ -47,7 +47,7 @@ RSpec.describe DeployToken do
   describe '#ensure_token' do
     it 'ensures a token' do
       deploy_token.token = nil
-      deploy_token.save
+      deploy_token.save!
 
       expect(deploy_token.token).not_to be_empty
     end

spec/models/deployment_spec.rb

@@ -497,7 +497,7 @@ RSpec.describe Deployment do
 
     context 'when the SHA for the deployment does not exist in the repo' do
       it 'returns false' do
-        deployment.update(sha: Gitlab::Git::BLANK_SHA)
+        deployment.update!(sha: Gitlab::Git::BLANK_SHA)
         commit = project.commit
 
         expect(deployment.includes_commit?(commit)).to be false