fix iframe resize on auth dropdown opening

[akellbl4]

Mutation observer was listening for all of the elements. When Auth dropdown appears it renders images and triggering height recalculations.
Resize trigger on image load was introduced in favor of resizing iframe for users with slow internet (when images load later and we need to resize iframe accordingly)

Solution:
Listen to mutations only on block with comments.
Plus remove unnecessary triggers.

[codecov]

Codecov Report

Base: 58.12% // Head: 58.07% // Decreases project coverage by -0.05% ⚠️

Coverage data is based on head (1d41e81) compared to base (ffcef2f).
Patch coverage: 4.76% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1490      +/-   ##
==========================================
- Coverage   58.12%   58.07%   -0.06%     
==========================================
  Files         131      131              
  Lines        2909     2910       +1     
  Branches      743      743              
==========================================
- Hits         1691     1690       -1     
- Misses       1214     1216       +2     
  Partials        4        4              

Impacted Files	Coverage Δ
...rontend/apps/remark42/app/components/root/root.tsx	0.00% <0.00%> (ø)
...nd/apps/remark42/app/components/auth/auth.hooks.ts	92.30% <100.00%> (-0.10%)	⬇️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[github-actions]

size-limit report 📦

Path	Size
public/embed.mjs	2.03 KB (0%)
public/remark.mjs	72.54 KB (+0.03% 🔺)
public/remark.css	8.15 KB (0%)
public/last-comments.mjs	35.64 KB (0%)
public/last-comments.css	3.72 KB (-0.03% 🔽)
public/deleteme.mjs	12.05 KB (0%)
public/counter.mjs	749 B (0%)

[paskal]

I installed it on https://terrty.net/2022/self-hosted-comments-remark42/

Safari, Chrome first load in Incognito:

After refresh:

[akellbl4]

@paskal thank you for testing the fix. I see in prod env it behave slightly different.
Probably should be a good idea to introduce e2e here