Let sensors also export state interfaces of joints

[christophfroehlich]

• Let sensor export also state interfaces of joints
• Fix returned no state interfaces warning

[saikishor]

In general, LGTM

[saikishor]

Thanks for fixing it

[codecov]

Codecov Report

Attention: Patch coverage is 92.98246% with 4 lines in your changes missing coverage. Please review.

Project coverage is 87.96%. Comparing base (41d7393) to head (fde0180).

Files with missing lines	Patch %	Lines
...dware_interface/test/test_component_interfaces.cpp	93.61%	3 Missing ⚠️
...ce/include/hardware_interface/sensor_interface.hpp	87.50%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1885      +/-   ##
==========================================
- Coverage   88.01%   87.96%   -0.05%     
==========================================
  Files         121      121              
  Lines       12404    12448      +44     
  Branches     1105     1107       +2     
==========================================
+ Hits        10917    10950      +33     
- Misses       1083     1091       +8     
- Partials      404      407       +3     

Flag	Coverage Δ
unittests	87.96% <92.98%> (-0.05%)	⬇️

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

Files with missing lines	Coverage Δ
hardware_interface/src/resource_manager.cpp	73.39% <ø> (ø)
...e/test/test_component_interfaces_custom_export.cpp	88.79% <100.00%> (-0.10%)	⬇️
...ce/include/hardware_interface/sensor_interface.hpp	92.15% <87.50%> (-1.03%)	⬇️
...dware_interface/test/test_component_interfaces.cpp	96.32% <93.61%> (-1.30%)	⬇️

... and 1 file with indirect coverage changes