Plugin provider atp race condition (#172)

* Progress towards adding function expressions to the engine

* Added function support

* Fixes.

* Added workflow test cases with more complex expressions

* Addressed review feedback

* Remove unnecessary reference to the function names in descriptions

* More description changes

* Manually add special cases to prevent platform-specific behavior

* Added negative zeros to test cases

* Address review comments

* Change case

* Address review comments

* Address review comments

* Fix linting error and address review comment.

* Change descriptions for functions

* Address review comment

* Added namespaced scopes for step namespaces in input

* Use default namespace constant

* Apply scopes from sub-workflows

* Update invalid serialization detector for changes in SDK

* Fix linting errors

* Improved code and added initial tests for namespaced scopes

* Added unit tests for new ApplyScope functions

* Added integration tests for namespaced scoped workflows

* Added namespaces for referenced items in scopes

* Upgrade to go SDK pre-release

* Addressed review comments

* Clarify stage IDs in comment examples

* Addressed review comments

* Fixed race condition for atp client field

* Move instantiation out of locked region

internal/step/plugin/provider.go

@@ -886,10 +886,12 @@ func (r *runningStep) deployStage() (deployer.Plugin, error) {
 
 func (r *runningStep) startStage(container deployer.Plugin) error {
 	r.logger.Debugf("Starting stage for step %s/%s", r.runID, r.pluginStepID)
+	atpClient := atp.NewClientWithLogger(container, r.logger)
 	r.lock.Lock()
 	previousStage := string(r.currentStage)
 	r.currentStage = StageIDStarting
 	inputRecievedEarly := false
+	r.atpClient = atpClient
 
 	var runInput any
 	select {
@@ -940,7 +942,6 @@ func (r *runningStep) startStage(container deployer.Plugin) error {
 			return fmt.Errorf("step closed while waiting for run configuration")
 		}
 	}
-	r.atpClient = atp.NewClientWithLogger(container, r.logger)
 
 	inputSchema, err := r.atpClient.ReadSchema()
 	if err != nil {