Reject duplicate state/command interfaces after configuring the controller

[saikishor]

We've found a situation where the controller upon reconfiguring says that the controller interfaces are claimed already, even though they are not. Upon verifying, I've seen that when we reconfigure the controller and the controller required interfaces are not performed an internal cleanup, it might end up with duplicated interfaces and will cause this behaviour.

I've observed that with the forward_command_controller, every time you run a reconfigure, it adds the same info again to the command_interface_types_; it is missing a clear before that.

https://github.com/ros-controls/ros2_controllers/blob/0fb4fc68df5b4ef05b01aba9984fb22940f0a76d/forward_command_controller/src/forward_command_controller.cpp#L47-L51

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 7 lines in your changes missing coverage. Please review.

Project coverage is 89.57%. Comparing base (3aa38b0) to head (d81d6d2).

Files with missing lines	Patch %	Lines
controller_manager/src/controller_manager.cpp	66.66%	3 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2090      +/-   ##
==========================================
+ Coverage   89.54%   89.57%   +0.03%     
==========================================
  Files         139      139              
  Lines       15125    15160      +35     
  Branches     1283     1286       +3     
==========================================
+ Hits        13543    13579      +36     
+ Misses       1096     1091       -5     
- Partials      486      490       +4     

Flag	Coverage Δ
unittests	89.57% <83.33%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
.../include/controller_manager/controller_manager.hpp	96.87% <ø> (ø)
...ller_manager/test/test_controller_manager_srvs.cpp	99.33% <100.00%> (+0.01%)	⬆️
controller_manager/src/controller_manager.cpp	76.29% <66.66%> (+0.02%)	⬆️

... and 2 files with indirect coverage changes

[christophfroehlich]

Thx for the fix, lgtm.