Tests: Playwright test timeouts (#7231)

## Summary

See where we can use proper DOM waiting instead of waitForTimeout.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7231-WIP-Playwright-test-timeouts-2c36d73d3650812b966ac3d9c338dfd4)
by [Unito](https://www.unito.io)

browser_tests/tests/subgraph.spec.ts

@@ -308,8 +308,6 @@ test.describe('Subgraph Operations', () => {
         }
       })
 
-      // Wait for dialog to appear
-      await comfyPage.page.waitForTimeout(200)
       await comfyPage.nextFrame()
 
       await comfyPage.page.waitForSelector(SELECTORS.promptDialog, {
@@ -656,7 +654,6 @@ test.describe('Subgraph Operations', () => {
 
       await comfyPage.rightClickSubgraphInputSlot('text')
       await comfyPage.clickLitegraphContextMenuItem('Remove Slot')
-      await comfyPage.page.waitForTimeout(200)
 
       // Wait for breadcrumb to be visible
       await comfyPage.page.waitForSelector(SELECTORS.breadcrumb, {
@@ -673,7 +670,6 @@ test.describe('Subgraph Operations', () => {
       await homeBreadcrumb.waitFor({ state: 'visible' })
       await homeBreadcrumb.click()
       await comfyPage.nextFrame()
-      await comfyPage.page.waitForTimeout(300)
 
       // Check that the subgraph node has no widgets after removing the text slot
       const widgetCount = await comfyPage.page.evaluate(() => {