test: disable missing model warnings in browser tests (#9513)

Disable missing model warnings in browser tests by default.

Browser tests run without model files on disk, so workflows that embed
model metadata can render differently in CI than the test actually
intends to cover. The viewport screenshot golden had started depending
on the missing-model popup even though the test is only about restoring
an offscreen viewport.

Set `Comfy.Workflow.ShowMissingModelsWarning` to `false` in the shared
Playwright fixture, keep the missing-model dialog coverage by explicitly
enabling the setting in the dialog tests, and update the viewport
screenshot expectation to the no-popup rendering.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9513-test-disable-missing-model-warnings-in-browser-tests-31b6d73d365081d1908bfe11ec0c3bc2)
by [Unito](https://www.unito.io)

browser_tests/assets/viewport/default-viewport-saved-offscreen.json

@@ -36,14 +36,7 @@
       "properties": {
         "Node name for S&R": "CheckpointLoaderSimple",
         "cnr_id": "comfy-core",
-        "ver": "0.3.65",
-        "models": [
-          {
-            "name": "v1-5-pruned-emaonly-fp16.safetensors",
-            "url": "https://huggingface.co/Comfy-Org/stable-diffusion-v1-5-archive/resolve/main/v1-5-pruned-emaonly-fp16.safetensors?download=true",
-            "directory": "checkpoints"
-          }
-        ]
+        "ver": "0.3.65"
       },
       "widgets_values": ["v1-5-pruned-emaonly-fp16.safetensors"]
     },

browser_tests/fixtures/ComfyPage.ts

@@ -432,7 +432,10 @@ export const comfyPageFixture = base.extend<{
         'Comfy.VueNodes.AutoScaleLayout': false,
         // Disable toast warning about version compatibility, as they may or
         // may not appear - depending on upstream ComfyUI dependencies
-        'Comfy.VersionCompatibility.DisableWarnings': true
+        'Comfy.VersionCompatibility.DisableWarnings': true,
+        // Browser tests should opt into missing-model warnings explicitly so
+        // workflows do not render differently based on models present on disk.
+        'Comfy.Workflow.ShowMissingModelsWarning': false
       })
     } catch (e) {
       console.error(e)

browser_tests/tests/dialog.spec.ts

@@ -89,6 +89,17 @@ test.describe('Execution error', () => {
 })
 
 test.describe('Missing models warning', () => {
+  test('Should be disabled by default in browser tests', async ({
+    comfyPage
+  }) => {
+    await comfyPage.workflow.loadWorkflow('missing/missing_models')
+
+    const dialogTitle = comfyPage.page.getByText(
+      'This workflow is missing models'
+    )
+    await expect(dialogTitle).not.toBeVisible()
+  })
+
   test.beforeEach(async ({ comfyPage }) => {
     await comfyPage.settings.setSetting(
       'Comfy.Workflow.ShowMissingModelsWarning',