Add Nearby Tasks Widget in task review

[CollinBeczak]

Purpose: To help reviewers see if there are any nearby tasks that should've been completed with the task, or task bundle submitted.

[codecov-commenter]

Codecov Report

Merging #2063 (746bd4f) into develop (d2d0792) will decrease coverage by 0.10%.
Report is 12 commits behind head on develop.
The diff coverage is 11.95%.

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@@             Coverage Diff             @@
##           develop    #2063      +/-   ##
===========================================
- Coverage    25.05%   24.95%   -0.10%     
===========================================
  Files          635      640       +5     
  Lines        21489    22167     +678     
  Branches      6532     6826     +294     
===========================================
+ Hits          5383     5531     +148     
- Misses       13502    13910     +408     
- Partials      2604     2726     +122     

Files Changed	Coverage Δ
src/components/ReviewTaskPane/ReviewTaskPane.js	12.90% <ø> (ø)
src/components/TaskPane/PublicTaskPane.js	21.42% <ø> (ø)
src/components/TaskPane/TaskPane.js	4.90% <ø> (ø)
...dgets/ReviewNearbyTasksWidget/TaskMarkerContent.js	0.00% <0.00%> (ø)
src/components/Widgets/widget_registry.js	50.00% <ø> (ø)
...ReviewNearbyTasksWidget/ReviewNearbyTasksWidget.js	4.41% <4.41%> (ø)
src/components/TaskClusterMap/TaskClusterMap.js	33.51% <57.14%> (+2.78%)	⬆️

... and 17 files with indirect coverage changes

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[AndrewPhilbin]

I'm getting an error because of a missing prevProps argument/parameter in the componentWillUnmount lifecycle for the ReviewNearbyTasksWidget:

componentWillUnmount() {
    const challengeId = _get(this.props.task, 'parent.id');
    if (_isFinite(challengeId)) {
      this.props.unsubscribeFromChallengeTaskMessages(challengeId);
    }

    if (
      _isFinite(_get(this.props, 'task.id')) &&
      _isFinite(_get(prevProps, 'task.id')) &&
      this.props.task.id !== prevProps.task.id
    ) {
      this.props.resetSelectedTasks();
    } else if (
      this.props.task &&
      this.props.selectedTasks &&
      !this.props.isTaskSelected(this.props.task.id)
    ) {
      this.props.selectTasks([this.props.task]);
    }
  }

Adding prevProps as an argument seems to fix:

componentWillUnmount(prevProps) {
  ...
}