Adds unexplored tasks to minimap

[kevinjtwu]

Resolves #3170

On page load, render all tasks (only time this will be done). Every time task is completed, update only the new current task (render: erase gray and draw red/green) once old current task has ended. If user jumps to another location within the same neighborhood, store old current task (incomplete) right before new current task is set. Then once new current task is set, rerender the old current task.

Before/After screenshots (if applicable)

Testing instructions

1. Navigate to Explore page
2. See minimap
3. Jump within neighborhood by selecting Jump in left side bar, then 'I want to explore another area!' then 'Go to a new location in this neighborhood'

Things to check before submitting the PR

• I've written a descriptive PR title.
• I've added/updated comments for large or confusing blocks of code.
• I've included before/after screenshots above.

[misaugstad]

This looks really good! I'm glad that after all the hard work, the code changes ended up looking rather simple. That generally means that it was done well :)

I just renamed a function and simplified an if statement, nothing major at all.

I am going to wait to merge, likely until after @crescendochu and @iamZhihanZhang are done with their current user study. But consider it approved!!