Don't save empty JS expressions as JS

packages/builder/src/components/common/bindings/DrawerBindableInput.svelte

@@ -4,10 +4,9 @@
     readableToRuntimeBinding,
     runtimeToReadableBinding,
   } from "dataBinding"
-
   import ClientBindingPanel from "components/common/bindings/ClientBindingPanel.svelte"
   import { createEventDispatcher, setContext } from "svelte"
-  import { isJSBinding } from "@budibase/string-templates"
+  import { isJSBinding, decodeJSBinding } from "@budibase/string-templates"
   import { builderStore } from "stores/builder"
 
   export let panel = ClientBindingPanel
@@ -35,7 +34,12 @@
   $: isJS = isJSBinding(value)
 
   const saveBinding = () => {
-    onChange(tempValue)
+    // Don't bother saving empty JS expressions as JS
+    let val = tempValue
+    if (decodeJSBinding(tempValue)?.trim() === "") {
+      val = null
+    }
+    onChange(val)
     onBlur()
     builderStore.propertyFocus()
     bindingDrawer.hide()