Update journeys and challenges search bar

[shah-esha]

Summary

This pull request implements additional and fixes current search features in both Journeys and Challenges.

• implemented searching by difficulty
• simplified code

Remaining TODOs:

• update documentation for both Journeys and Challenges
• test through simulation
• testing outside of just simulating the app locally

[dti-github-bot]

[diff-counting] Significant lines: 115.

[3TTemi]

Nice job on this fix! Make sure to remove the print debug statements, this should be done before you ever make a PR. Also for better readability, try and revisit some of the variable names, moving away from "event.examplefield" to ensure it's clear which entity the difficulty, name, and other fields refer to (see my comment in the journey code for reference).

[BrianLa0616]

In a specific PR regarding addressing both cleaning up challenges and journeys, I would have a separate util function that can handle both the matching/searching feature in the journeys and challenges page. This can be done in another PR though.