[ControllerInterface] Avoid warning about conversion from int64_t to unsigned int (backport #1173)

[mergify]

Without this there is a warning. For what I found the best way is to do static cast.

ros2_control/controller_interface/src/controller_interface_base.cpp:88:67: warning: conversion from ‘int64_t’{aka ‘long int’} to ‘unsigned int’ may change value [-Wconversion]
88 |     update_rate_ = get_node()->get_parameter("update_rate").as_int();

#GitHub-Programming-Rocks

---

This is an automatic backport of pull request #1173 done by Mergify.

[mergify]

Cherry-pick of 2569b76 has failed:

On branch mergify/bp/humble/pr-1173
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit 2569b76.
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Unmerged paths:
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	both modified:   controller_interface/src/controller_interface_base.cpp

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.98%. Comparing base (a03055d) to head (1dd8351).
Report is 2 commits behind head on humble.

Additional details and impacted files

@@           Coverage Diff           @@
##           humble    #1631   +/-   ##
=======================================
  Coverage   86.98%   86.98%           
=======================================
  Files          97       97           
  Lines        7508     7508           
  Branches      677      677           
=======================================
  Hits         6531     6531           
  Misses        690      690           
  Partials      287      287           

Flag	Coverage Δ
unittests	86.98% <100.00%> (ø)

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Files	Coverage Δ
...roller_interface/src/controller_interface_base.cpp	84.78% <100.00%> (ø)