How to reproduce:
1. Create a new project in Unity ID > Projects > Create New Project (https://developer.cloud.unity3d.com/projects/create/)
2. Enable Unity Collaborate in the Overview of the project
3. Download the Project from the Unity Cloud via Unity Hub
4. Open the Project
5. Open the Collaborate window from the Services window
6. Click the "Open the Collaborate toolbar" option

Expected result: the Collaborate toolbar opens
Actual result: the Collaborate toolbar doesn't open

Reproducible with: 2018.3.0a9, 2018.3.14f1, 2018.4.21f1, 2019.1.0a14
Not reproducible with: 2017.4.39f1, 2018.3.0a8, 2019.1.0b1, 2019.3.10f1, 2020.1.0b5, 2020.2.0a7

Notes:
-This is fixed by resetting packages to defaults
-The "manifest.json" doesn't contain any packages after the project is downloaded and opened
-The Collab drop-down menu button at the toolbar is also missing in the project