[backport rh-test] fix: improve template URL loading UX and prevent re-triggering (#6654)

Backport of #6593 to `rh-test`

Automatically created by backport workflow.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6654-backport-rh-test-fix-improve-template-URL-loading-UX-and-prevent-re-triggering-2a86d73d36508163834fdea17353ed37)
by [Unito](https://www.unito.io)

Co-authored-by: Christian Byrne <cbyrne@comfy.org>
Co-authored-by: Christian Byrne <c.byrne@comfy.org>

tests-ui/tests/platform/workflow/templates/composables/useTemplateUrlLoader.test.ts

@@ -14,10 +14,14 @@ import { useTemplateUrlLoader } from '@/platform/workflow/templates/composables/
 
 // Mock vue-router
 let mockQueryParams: Record<string, string | undefined> = {}
+const mockRouterReplace = vi.fn()
 
 vi.mock('vue-router', () => ({
   useRoute: vi.fn(() => ({
     query: mockQueryParams
+  })),
+  useRouter: vi.fn(() => ({
+    replace: mockRouterReplace
   }))
 }))
 
@@ -217,4 +221,43 @@ describe('useTemplateUrlLoader', () => {
       life: 3000
     })
   })
+
+  it('removes template params from URL after successful load', async () => {
+    mockQueryParams = {
+      template: 'flux_simple',
+      source: 'custom',
+      other: 'param'
+    }
+
+    const { loadTemplateFromUrl } = useTemplateUrlLoader()
+    await loadTemplateFromUrl()
+
+    expect(mockRouterReplace).toHaveBeenCalledWith({
+      query: { other: 'param' }
+    })
+  })
+
+  it('removes template params from URL even on error', async () => {
+    mockQueryParams = { template: 'invalid', source: 'custom', other: 'param' }
+    mockLoadWorkflowTemplate.mockResolvedValueOnce(false)
+
+    const { loadTemplateFromUrl } = useTemplateUrlLoader()
+    await loadTemplateFromUrl()
+
+    expect(mockRouterReplace).toHaveBeenCalledWith({
+      query: { other: 'param' }
+    })
+  })
+
+  it('removes template params from URL even on exception', async () => {
+    mockQueryParams = { template: 'flux_simple', other: 'param' }
+    mockLoadTemplates.mockRejectedValueOnce(new Error('Network error'))
+
+    const { loadTemplateFromUrl } = useTemplateUrlLoader()
+    await loadTemplateFromUrl()
+
+    expect(mockRouterReplace).toHaveBeenCalledWith({
+      query: { other: 'param' }
+    })
+  })
 })