Add Widget Dialog Fixes

[Gold872]

• Switching tabs while dragging no longer breaks everything
• Reorganized (and improved) add widget dialog

[codecov]

Codecov Report

Attention: Patch coverage is 77.58621% with 26 lines in your changes missing coverage. Please review.

Project coverage is 75.84%. Comparing base (bf6f698) to head (4ef8d0d).

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
lib/pages/dashboard_page.dart	79.78%	19 Missing ⚠️
lib/widgets/dialog_widgets/layout_drag_tile.dart	42.85%	4 Missing ⚠️
lib/widgets/network_tree/networktables_tree.dart	80.00%	2 Missing ⚠️
lib/widgets/tab_grid.dart	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #193      +/-   ##
==========================================
- Coverage   75.91%   75.84%   -0.07%     
==========================================
  Files          79       79              
  Lines        8626     8648      +22     
==========================================
+ Hits         6548     6559      +11     
- Misses       2078     2089      +11     

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