Updated rs_launch configurations

[Arun-Prasad-V]

Issue:

• In rs_multi_camera_launch.py, '1' and '2' are appended as suffix of actual param names listed in rs_launch.py. For example: enable_infra param name from rs_launch.py becomes enable_infra1 and enable_infra2. But, there are already params with those names in rs_launch.py. This leads to misconfiguration of params.

Root cause:

• Misconfiguration happens because while running rs_multi_camera_launch.py both actual and appended param names are getting registered
• No need to register actual param names from rs_launch.py
• Should register only appended param names

Fix:

• Updating rs_launch.py to support getting only required param names dynamically and register them

[SamerKhshiboun]

LGTM, thanks for the fix Arun !