fix(core): explicitly cast signal node value to String

If the computed's `toString` is called and `node.value` is a Symbol, the browser will throw an exception `ERROR TypeError: Cannot convert a Symbol value to a string`

Symbols cannot be implicitly changed to strings. This change changes the conversion to be explicit by wrapping `node.value` with `String()`

This can be reproduced if you create a computed with `createComputed(computation, equal)` and call `toString()` while `node.value` is something like `Symbol(UNSET)`

Author: andrewseguin

packages/core/primitives/signals/src/computed.ts

@@ -84,7 +84,7 @@ export function createComputed<T>(
   (computed as ComputedGetter<T>)[SIGNAL] = node;
   if (typeof ngDevMode !== 'undefined' && ngDevMode) {
     const debugName = node.debugName ? ' (' + node.debugName + ')' : '';
-    computed.toString = () => `[Computed${debugName}: ${node.value}]`;
+    computed.toString = () => `[Computed${debugName}: ${String(node.value)}]`;
   }
 
   runPostProducerCreatedFn(node);

packages/core/primitives/signals/src/linked_signal.ts

@@ -94,7 +94,7 @@ export function createLinkedSignal<S, D>(
   getter[SIGNAL] = node;
   if (typeof ngDevMode !== 'undefined' && ngDevMode) {
     const debugName = node.debugName ? ' (' + node.debugName + ')' : '';
-    getter.toString = () => `[LinkedSignal${debugName}: ${node.value}]`;
+    getter.toString = () => `[LinkedSignal${debugName}: ${String(node.value)}]`;
   }
 
   runPostProducerCreatedFn(node);

packages/core/primitives/signals/src/signal.ts

@@ -63,7 +63,7 @@ export function createSignal<T>(
   (getter as any)[SIGNAL] = node;
   if (typeof ngDevMode !== 'undefined' && ngDevMode) {
     const debugName = node.debugName ? ' (' + node.debugName + ')' : '';
-    getter.toString = () => `[Signal${debugName}: ${node.value}]`;
+    getter.toString = () => `[Signal${debugName}: ${String(node.value)}]`;
   }
 
   runPostProducerCreatedFn(node);