[sr_edc_launch] robot_description arg quotes misplaced

[guihomework]

in sr_edc.launch and in bimanual, the launch arg robot_description is not a real urdf loaded directly but a file passed to xacro. because it is passed to xacro one might want to also give options to xacro for instance

--inorder '$(find agni_description)/robots/single.urdf.xacro' PREFIX:=$(arg prefix) TOOL:=$(arg hand_type) SIM:=0 CALIB:=default PARENT:='-' 

the problem is that the command has quotes around this robot_description variable which forces xacro to take the whole as a string and not as separate arguments.

<param name="robot_description" command="$(find xacro)/xacro.py $(arg robot_description)" />

The quotes were added to handle the possible spaces in the filepath but the user should take care of that when passing the variable.

The solution is easy and a PR will be given immediately

[guihomework]

is fixed so close