chore: modify parameter dynamic immutability behavior (#18583)

Immutability behavior is determined by the current build, not affected by the previous

enterprise/coderd/testdata/parameters/dynamicimmutable/main.tf

@@ -0,0 +1,23 @@
+terraform {
+  required_providers {
+    coder = {
+      source = "coder/coder"
+    }
+  }
+}
+
+data "coder_workspace_owner" "me" {}
+
+data "coder_parameter" "isimmutable" {
+  name    = "isimmutable"
+  type    = "bool"
+  mutable = true
+  default = "true"
+}
+
+data "coder_parameter" "immutable" {
+  name    = "immutable"
+  type    = "string"
+  mutable = data.coder_parameter.isimmutable.value == "false"
+  default = "Hello World"
+}