fix(joint_state_broadcaster): suppress confusing warning for standard interfaces (backport #2276)

[mergify]

Description

This PR fixes the confusing warning message from JointStateBroadcaster when using standard interfaces like velocity with the default mapping.

Problem

When configuring the broadcaster with standard interfaces:

rotor_state_broadcaster:
  ros__parameters:
    joints: [rotor/1, rotor/2, rotor/3, rotor/4]
    interfaces: [velocity]

The following confusing warning was displayed:

Mapping from 'velocity' to interface 'velocity' will not be done, because 'velocity' is defined in 'interface' parameter.

This warning is confusing because:

1. The user didn't configure any custom mapping
2. The data is being published correctly to the velocity field
3. The warning suggests something is wrong when everything works as expected

Solution

The warning is now only displayed when there's an actual custom mapping being ignored (i.e., when the interface name differs from the JointState field name).

For example, if someone had:

interfaces: [velocity]
map_interface_to_joint_state:
  velocity: custom_velocity_interface

Then the warning would still be shown because the custom mapping custom_velocity_interface -> velocity would be ignored.

But for the standard case where interfaces: [velocity] and the default mapping velocity -> velocity, no warning is shown because no mapping is needed.

Changes

• Modified joint_state_broadcaster.cpp to only print the warning when interface != interface_to_map

Related Issue

Fixes #2261

---

This is an automatic backport of pull request #2276 done by Mergify.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.88%. Comparing base (9a750b8) to head (0d9c702).
⚠️ Report is 2 commits behind head on jazzy.

Additional details and impacted files

@@            Coverage Diff             @@
##            jazzy    #2333      +/-   ##
==========================================
- Coverage   84.91%   84.88%   -0.04%     
==========================================
  Files         154      154              
  Lines       15271    15378     +107     
  Branches     1351     1351              
==========================================
+ Hits        12968    13053      +85     
- Misses       1811     1834      +23     
+ Partials      492      491       -1     

Flag	Coverage Δ
unittests	84.88% <100.00%> (-0.04%)	⬇️

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

Files with missing lines	Coverage Δ
..._state_broadcaster/src/joint_state_broadcaster.cpp	88.70% <ø> (+0.53%)	⬆️
..._broadcaster/test/test_joint_state_broadcaster.cpp	96.98% <100.00%> (-0.37%)	⬇️

... and 19 files with indirect coverage changes

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