feat(neon_framework): Display blurhash for rich text file previews

[provokateurin]

Closes #2411

This was too easy 😅

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 28.86%. Comparing base (0cf074e) to head (0efa671).
Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2614   +/-   ##
=======================================
  Coverage   28.85%   28.86%           
=======================================
  Files         370      370           
  Lines      136528   136530    +2     
=======================================
+ Hits        39396    39403    +7     
+ Misses      97132    97127    -5     

Flag	Coverage Δ		*Carryforward flag
account_repository	98.47% <ø> (ø)
cookie_store	99.48% <ø> (ø)		Carriedforward from 0cf074e
dashboard_app	96.05% <ø> (ø)
dynamite	31.05% <ø> (ø)		Carriedforward from 0cf074e
dynamite_end_to_end_test	61.69% <ø> (ø)		Carriedforward from 0cf074e
dynamite_runtime	85.40% <ø> (ø)		Carriedforward from 0cf074e
interceptor_http_client	97.18% <ø> (ø)		Carriedforward from 0cf074e
neon_dashboard	96.05% <ø> (ø)		Carriedforward from 0cf074e
neon_framework	61.33% <100.00%> (+0.16%)	⬆️
neon_http_client	97.50% <ø> (ø)		Carriedforward from 0cf074e
neon_notifications	100.00% <ø> (ø)		Carriedforward from 0cf074e
neon_storage	94.66% <ø> (ø)		Carriedforward from 0cf074e
neon_talk	99.45% <ø> (ø)		Carriedforward from 0cf074e
nextcloud	24.33% <ø> (ø)		Carriedforward from 0cf074e
notifications_app	97.40% <ø> (ø)
notifications_push_repository	98.11% <ø> (ø)
sort_box	90.90% <ø> (ø)		Carriedforward from 0cf074e
talk_app	98.94% <ø> (ø)

*This pull request uses carry forward flags. Click here to find out more.

Files with missing lines	Coverage Δ
...neon_framework/lib/src/widgets/rich_text/file.dart	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes