touchscreen: wrong url argh (#3790)

fix url

### Change Type

<!-- ❗ Please select a 'Scope' label ❗️ -->

- [x] `sdk` — Changes the tldraw SDK
- [ ] `dotcom` — Changes the tldraw.com web app
- [ ] `docs` — Changes to the documentation, examples, or templates.
- [ ] `vs code` — Changes to the vscode plugin
- [ ] `internal` — Does not affect user-facing stuff

<!-- ❗ Please select a 'Type' label ❗️ -->

- [x] `bugfix` — Bug fix
- [ ] `feature` — New feature
- [ ] `improvement` — Improving existing features
- [ ] `chore` — Updating dependencies, other boring stuff
- [ ] `galaxy brain` — Architectural changes
- [ ] `tests` — Changes to any test code
- [ ] `tools` — Changes to infrastructure, CI, internal scripts,
debugging tools, etc.
- [ ] `dunno` — I don't know

apps/dotcom/src/pages/public-touchscreen-side-panel.tsx

@@ -15,8 +15,8 @@ export function Component() {
 			})
 			const sidePanelClient = await session.createSidePanelClient()
 			await sidePanelClient.setCollaborationStartingState({
-				sidePanelUrl: `${window.location.origin}/tc-side`,
-				mainStageUrl: `${window.location.origin}/tc`,
+				sidePanelUrl: `${window.location.origin}/ts-side`,
+				mainStageUrl: `${window.location.origin}/ts`,
 				additionalData: undefined,
 			})
 		}