Use ValueListenableBuilder for NT widget state

[Gold872]

Instead of using StreamBuilders which can be slow, constantly create futures and timers, and don't work well with multi-topic widgets, ValueListenableBuilders only get called when the subscription actually updates.

CPU usage has decreased by 10-15%

[codecov]

Codecov Report

Attention: Patch coverage is 90.51522% with 81 lines in your changes missing coverage. Please review.

Project coverage is 66.15%. Comparing base (076925d) to head (827a091).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...gets/nt_widgets/multi-topic/robot_preferences.dart	72.58%	17 Missing ⚠️
lib/widgets/nt_widgets/nt_widget.dart	77.19%	13 Missing ⚠️
lib/services/nt4_client.dart	25.00%	6 Missing ⚠️
lib/services/nt_connection.dart	0.00%	6 Missing ⚠️
...ets/nt_widgets/multi-topic/basic_swerve_drive.dart	90.00%	5 Missing ⚠️
..._widgets/multi-topic/three_axis_accelerometer.dart	91.37%	5 Missing ⚠️
...widgets/nt_widgets/multi-topic/encoder_widget.dart	89.18%	4 Missing ⚠️
...b/widgets/network_tree/networktables_tree_row.dart	25.00%	3 Missing ⚠️
...ets/nt_widgets/multi-topic/differential_drive.dart	90.32%	3 Missing ⚠️
...b/widgets/nt_widgets/multi-topic/field_widget.dart	88.46%	3 Missing ⚠️
... and 8 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #110      +/-   ##
==========================================
+ Coverage   63.94%   66.15%   +2.21%     
==========================================
  Files          77       77              
  Lines        7984     8014      +30     
==========================================
+ Hits         5105     5302     +197     
+ Misses       2879     2712     -167     

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