Update markdown parser config to fix issue with broken line breaks handling in resource descriptions

[kollivier]

Summary

Although we have a markdown parser rendering descriptions, it turns out when we use the 'zero' parser it disables the break handling we are using it for resulting in descriptions not being able to be multi-line.

This PR fixes that by using the default markdown parser. This does have the side-effect of rendering more markdown syntax. I think this is okay if we treat it as an undocumented feature, and use it sparingly until we have some strong evidence that a majority of users are on 0.15 or above.

Reviewer guidance

Ping me if you want a channel to test this with, basically testing with any description containing line breaks will show the issue.

References

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Contributor Checklist

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• Contributor has fully tested the PR manually
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Reviewer Checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[codecov]

Codecov Report

Merging #7613 into release-v0.14.x will decrease coverage by 0.00%.
The diff coverage is 0.00%.

Impacted Files	Coverage Δ
...bri/plugins/learn/assets/src/views/ContentPage.vue	16.49% <0.00%> (ø)
kolibri/core/content/utils/check_schema_db.py	91.30% <0.00%> (-8.70%)	⬇️
.../core/deviceadmin/management/commands/dbrestore.py	76.56% <0.00%> (ø)