fix: add worksheet 4 student challenge url

[razvan-pro]

This change is 

[faucomte97]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @razvan-pro)

---

aimmo/worksheets.py line 224 at r1 (raw file):

""",
        active_image_path="images/worksheets/modern_active.png",
        description="After successfully collecting all the missing artefacts from the first time checkpoint, you arrive at what looks like the 21st century. You recognise some cars parked here and there, old-fashioned roads and houses like the ones your history teacher told you about. On the bright side, you seem to be alone and safe to walk around... for now. A more recent timeline doesn’t make artefacts easier to find, though. Or at least not the right ones. In this timeline there seems to be an amount of falsified objects that resemble the ones you’re looking for, but aren’t quite genuine. These will have no value in the museum. Your navigation system will be able to tell you whether an object is genuine or not, but it’s up to you to decide which ones to bring back!",

Yeaaah this needs to be reviewed and changed. It's not relevant to what the worksheet is anymore.
I'd have something like:

After successfully collecting all the missing artefacts from the first time checkpoint, you arrive at what looks like the 21st century. You recognise some cars parked here and there, just like the ones your history teacher told you about. A more recent timeline doesn’t make artefacts easier to find, though. Or at least not the right ones. In this timeline there seems to be some object which will have no value in the museum. Your navigation system will be able to tell you whether an object is genuine or not, but it’s up to you to decide which ones to bring back!

[faucomte97]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @razvan-pro)

[codecov]

Codecov Report

Merging #1663 (e5a4136) into master (7299ab3) will increase coverage by 19.98%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master    #1663       +/-   ##
===========================================
+ Coverage   67.98%   87.97%   +19.98%     
===========================================
  Files         165       38      -127     
  Lines        3377     1048     -2329     
  Branches      283      159      -124     
===========================================
- Hits         2296      922     -1374     
+ Misses       1054      103      -951     
+ Partials       27       23        -4     

Impacted Files	Coverage Δ
aimmo/worksheets.py
aimmo/csp_config.py
game_frontend/src/components/icons/Play.js
game_frontend/src/containers/Game/index.js
aimmo/templatetags/players_utils.py
aimmo/serializers.py
aimmo/migrations/0011_reset_game_tokens.py
game_frontend/src/babylon/interfaces.ts
game_frontend/src/components/Code/index.js
...ame_frontend/src/babylon/assetPacks/wrongFuture.ts
... and 119 more