Fix #2493 by removing the unused joint to camera_rgb_frame

[Darkproduct]

It looks like camera_rgb_link is now camera_link e3ee2da

Basic Info

Info	Please fill out this column
Ticket(s) this addresses	#2493
Primary OS tested on	Ubuntu
Robotic platform tested on	none, Gazebo 11.5

Description of contribution in a few bullet points

Fix the waffle.model file

Description of documentation updates required from your changes

None

Future work that may be required in bullet points

None

For Maintainers:

• Check that any new parameters added are updated in navigation.ros.org
• Check that any significant change is added to the migration guide
• Check that any new functions have Doxygen added
• Check that any new features have test coverage
• Check that any new plugins is added to the plugins page
• If BT Node, Additionally: add to BT's XML index of nodes for groot, BT package's readme table, and BT library lists