csi: rework tests exercising CSI plugin lifecycle state

The existing CSI tests for the state store incorrectly modeled the
updates we received from servers vs those we received from clients,
leading to test assertions that passed when they should not.

Rework the tests to clarify each step in the lifecycle.

nomad/mock/mock.go

@@ -2178,6 +2178,39 @@ func CSIVolume(plugin *structs.CSIPlugin) *structs.CSIVolume {
 	}
 }
 
+func CSIPluginJob(pluginType structs.CSIPluginType, pluginID string) *structs.Job {
+
+	job := new(structs.Job)
+
+	switch pluginType {
+	case structs.CSIPluginTypeController:
+		job = Job()
+		job.ID = fmt.Sprintf("mock-controller-%s", pluginID)
+		job.Name = "job-plugin-controller"
+		job.TaskGroups[0].Count = 2
+	case structs.CSIPluginTypeNode:
+		job = SystemJob()
+		job.ID = fmt.Sprintf("mock-node-%s", pluginID)
+		job.Name = "job-plugin-node"
+	case structs.CSIPluginTypeMonolith:
+		job = SystemJob()
+		job.ID = fmt.Sprintf("mock-monolith-%s", pluginID)
+		job.Name = "job-plugin-monolith"
+	}
+
+	job.TaskGroups[0].Name = "plugin"
+	job.TaskGroups[0].Tasks[0].Name = "plugin"
+	job.TaskGroups[0].Tasks[0].Driver = "docker"
+	job.TaskGroups[0].Tasks[0].Services = nil
+	job.TaskGroups[0].Tasks[0].CSIPluginConfig = &structs.TaskCSIPluginConfig{
+		ID:       pluginID,
+		Type:     pluginType,
+		MountDir: "/csi",
+	}
+	job.Canonicalize()
+	return job
+}
+
 func Events(index uint64) *structs.Events {
 	return &structs.Events{
 		Index: index,