chore: Add extension-tile-playground package to release-please manifest (#1428)

extension-tile-playground package was not part of the release-please
manifest. This meant release-please does not update its package.json
with every release PR.
For context:
Our release PR branch was failing on build. Why?
1. `extension-tile-playground` depends on `extension-sdk`.
`extension-sdk` was on 23.20.1.
2. We added a breaking change to it and had to update
`extension-tile-playground`. All done in 1 PR.
3. Latest main branch built successfully since since the playground is
pointing to `extension-sdk` 23.20.1 which is latest in repo.
4. However release-please created a release PR that bumped
`extension-sdk` to 24.0.0, BUT did not bump `extension-tile-playground`
package.json's `extension-sdk` dependency which stayed on 23.20.1
5. This forced yarn to pull in `extension-sdk` 23.20.1 from npm which
would not contain latest changes in repo, breaking the build.

Or so i think!

Author: jeremytchang

.release-please-manifest.json

@@ -18,6 +18,7 @@
   "packages/wholly-sheet": "0.5.51",
   "python": "23.20.1",
   "packages/extension-playground": "1.0.12",
+  "packages/extension-tile-playground": "1.0.0", 
   "packages/embed-services": "23.20.1",
   "packages/embed-components": "23.20.1"
 }

packages/extension-tile-playground/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@looker/extension-tile-playground",
-  "version": "22.10.1",
+  "version": "1.0.0",
   "description": "Extension Tile Playground",
   "main": "lib/index.js",
   "module": "lib/esm/index.js",