[2.6.16] enforcing checksum algorithm when joining breakout rooms

[paulseto]

Describe the bug
Joining a breakout room cause a checksum error.

To Reproduce
Steps to reproduce the behavior:

1. Update /etc/bigbluebutton/bbb-web.properties so it only support sha512

 supportedChecksumAlgorithms=sha512

2. Restart BBB with sudo bbb-conf --restart
3. Create a meeting and join with 4 users
4. Create and auto assign users to a breakout room
5. Attempt to join breakout room.

Expected behavior
Join breakout room.

Actual behavior
User is unable to join breakout room and url contains an error message.

Screenshots

Desktop (please complete the following information):
Test on Windows 10 with latest version of Edge, Chrome, and FireFox

Smartphone (please complete the following information):
None

Additional context
None