Increase default dashboard client timeout to 2 seconds

[urfeex]

The default timeout of 1 second can collide with certain actions. For example, the power_off command on PolyScope 5 takes 1 sec almost exactly until it sends the answer. With that, the timeout was right on the edge and led to a flaky integration test. Defaulting to 2 seconds should prevent those tests from failing randomly.

I'll add this commit to #1561 and #1562 once approved.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 15.29%. Comparing base (1b121b7) to head (0b3e470).
⚠️ Report is 508 commits behind head on main.

Files with missing lines	Patch %	Lines
ur_robot_driver/src/dashboard_client_ros.cpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##            main    #1564       +/-   ##
==========================================
+ Coverage   3.59%   15.29%   +11.70%     
==========================================
  Files         13       34       +21     
  Lines        947     3878     +2931     
  Branches     152      467      +315     
==========================================
+ Hits          34      593      +559     
- Misses       843     3268     +2425     
+ Partials      70       17       -53     

Flag	Coverage Δ
unittests	15.29% <0.00%> (+11.70%)	⬆️

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