fix: DH-17292 Handle disconnect from GridWidgetPlugin (#2086)

[mofojed]

• When the model is disconnected, we should just display an error. There's no option to reconnect, as the widget schema could change entirely
• By unloading the IrisGrid component, it's no longer throwing an error by trying to access table methods after a table.close()
• Fixes DH-17292 from Enterprise
  • Tested using the steps in the description

[codecov]

Codecov Report

Attention: Patch coverage is 69.69697% with 20 lines in your changes missing coverage. Please review.

Project coverage is 46.80%. Comparing base (1d8d9c3) to head (66ad013).

Files with missing lines	Patch %	Lines
...es/dashboard-core-plugins/src/GridWidgetPlugin.tsx	0.00%	8 Missing ⚠️
.../dashboard-core-plugins/src/PandasWidgetPlugin.tsx	0.00%	7 Missing ⚠️
...ges/dashboard-core-plugins/src/useIrisGridModel.ts	90.19%	5 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                @@
##           release/v0.85    #2357      +/-   ##
=================================================
+ Coverage          46.71%   46.80%   +0.09%     
=================================================
  Files                689      690       +1     
  Lines              38623    38646      +23     
  Branches            9809     9629     -180     
=================================================
+ Hits               18043    18089      +46     
- Misses             20528    20547      +19     
+ Partials              52       10      -42     

Flag	Coverage Δ
unit	46.80% <69.69%> (+0.09%)	⬆️

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