Fix DataGen not quite mirroring toAgentModels()

It should omit agent information when the workspace specifies no agents
and the name should combine the workspace and agent names.

src/main/kotlin/com/coder/gateway/models/WorkspaceAgentModel.kt

@@ -17,7 +17,7 @@ data class WorkspaceAgentModel(
     val agentID: UUID?,
     val workspaceID: UUID,
     val workspaceName: String,
-    val name: String, // Name of the workspace OR the agent if this is for an agent.
+    val name: String, // Name of the workspace OR workspace.agent if this is for an agent.
     val templateID: UUID,
     val templateName: String,
     val templateIconPath: String,

src/test/groovy/DataGen.groovy

@@ -5,12 +5,19 @@ import com.coder.gateway.sdk.v2.models.WorkspaceStatus
 import com.coder.gateway.sdk.v2.models.WorkspaceTransition
 
 class DataGen {
-    static WorkspaceAgentModel workspace(String name, String workspaceName = name) {
+    // Create a random workspace agent model.  If the workspace name is omitted
+    // then return a model without any agent bits, similar to what
+    // toAgentModels() does if the workspace does not specify any agents.
+    // TODO: Maybe better to randomly generate the workspace and then call
+    //       toAgentModels() on it.  Also the way an "agent" model can have no
+    //       agent in it seems weird; can we refactor to remove
+    //       WorkspaceAgentModel and use the original structs from the API?
+    static WorkspaceAgentModel workspace(String name, String workspaceName = "", UUID agentId = UUID.randomUUID()) {
         return new WorkspaceAgentModel(
+                workspaceName == "" ? null : agentId,
                 UUID.randomUUID(),
-                UUID.randomUUID(),
-                workspaceName,
-                name,
+                workspaceName == "" ? name : workspaceName,
+                workspaceName == "" ? name : (workspaceName + "." + name),
                 UUID.randomUUID(),
                 "template-name",
                 "template-icon-path",