test: make closeMenu safe, use canvas for saveImageAndWebp

- closeMenu() now checks if close button exists before clicking
- saveImageAndWebp screenshots canvas instead of full page
- Delete widget golden images for regeneration

browser_tests/fixtures/ComfyPage.ts

@@ -371,8 +371,11 @@ export class ComfyPage {
   }
 
   async closeMenu() {
-    await this.page.locator('button.comfy-close-menu-btn').click()
-    await this.nextFrame()
+    const btn = this.page.locator('button.comfy-close-menu-btn')
+    if ((await btn.count()) > 0) {
+      await btn.click()
+      await this.nextFrame()
+    }
   }
 
   async clickDialogButton(prompt: string, buttonText: string = 'Yes') {

browser_tests/tests/saveImageAndWebp.spec.ts

@@ -29,7 +29,7 @@ test.describe(
         timeout: 30000
       })
 
-      await expect(comfyPage.page).toHaveScreenshot(
+      await expect(comfyPage.canvas).toHaveScreenshot(
         'save-image-and-webm-preview.png'
       )
     })