fix: use the new delete callback API

Toolbox provides a callback for scenarios that involve the env. deletion. This allows plugins to react
and clean the internal state. With the new TBX API, the delete callback API is deprecated in the favor
of a mutable state flow, a reactive approach that allows consumers to observe and react to state changes
over time.

Author: fioan89

src/main/kotlin/com/coder/toolbox/CoderRemoteEnvironment.kt

@@ -27,6 +27,7 @@ import com.squareup.moshi.Moshi
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
@@ -269,7 +270,7 @@ class CoderRemoteEnvironment(
         }
     }
 
-    override fun onDelete() {
+    override val deleteActionFlow: StateFlow<(() -> Unit)?> = MutableStateFlow {
         context.cs.launch {
             try {
                 client.removeWorkspace(workspace)