fix: add null check for component in awesome_map API fetcher

[takahashim]

In a Decidim environment I was testing, I encountered a case where the result from api.fetchAll() in the Fetcher.fetch() function (decidim/decidim_awesome/awesome_map/api/fetcher.js) returned {"component": null}.

In this case, accessing result.component[this.collection] in fetcher.js throws an error.

This PR adds a null check for result.component and calls onFinished() before returning early to prevent the error.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.75%. Comparing base (0119a5a) to head (9c76737).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #492      +/-   ##
==========================================
+ Coverage   92.35%   96.75%   +4.39%     
==========================================
  Files         166      166              
  Lines        4250     4250              
==========================================
+ Hits         3925     4112     +187     
+ Misses        325      138     -187     

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[microstudi]

Thanks!