Add new development assets and use in mocks/previews.

[pixlwave]

Follow on from #3569, this PR adds some specific assets for images, videos and avatars so that we're not building against the logo which is a circle with alpha.

Lots of snapshots, I tweaked a few so they render the full height rather than being clipped.

[github-actions]

	Warnings
⚠️	Some of the commits are missing ticket numbers. Please consider squashing all commits that don't have a tracking number.
⚠️	You seem to have made changes to views. Please consider adding screenshots.

Generated by 🚫 Danger Swift against 57a1365

[Velin92]

LGTM, no we have some diversity in testing images in previews

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.84%. Comparing base (7e5624f) to head (57a1365).
Report is 2 commits behind head on develop.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3581      +/-   ##
===========================================
+ Coverage    78.82%   78.84%   +0.01%     
===========================================
  Files          757      757              
  Lines        63843    63798      -45     
===========================================
- Hits         50325    50302      -23     
+ Misses       13518    13496      -22     

Flag	Coverage Δ
unittests	69.89% <100.00%> (-0.06%)	⬇️

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