fix(nextcloud): Fix WebDav path calculations for instances hosted at subpaths

[provokateurin]

Might fix saber-notes/saber#772

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 28.67%. Comparing base (049c925) to head (d68f74a).
Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
...account_repository/lib/src/models/credentials.dart	50.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2562   +/-   ##
=======================================
  Coverage   28.67%   28.67%           
=======================================
  Files         366      366           
  Lines      136296   136299    +3     
=======================================
+ Hits        39077    39079    +2     
- Misses      97219    97220    +1     

Flag	Coverage Δ		*Carryforward flag
account_repository	98.47% <50.00%> (-0.30%)	⬇️
cookie_store	99.48% <ø> (ø)		Carriedforward from 049c925
dashboard_app	96.05% <ø> (ø)
dynamite	31.05% <ø> (ø)		Carriedforward from 049c925
dynamite_end_to_end_test	61.69% <ø> (ø)		Carriedforward from 049c925
dynamite_runtime	85.40% <ø> (ø)		Carriedforward from 049c925
interceptor_http_client	97.18% <ø> (ø)		Carriedforward from 049c925
neon_dashboard	96.05% <ø> (ø)		Carriedforward from 049c925
neon_framework	59.20% <ø> (ø)
neon_http_client	97.50% <ø> (ø)
neon_notifications	100.00% <ø> (ø)		Carriedforward from 049c925
neon_storage	94.66% <ø> (ø)
neon_talk	99.45% <ø> (ø)		Carriedforward from 049c925
nextcloud	24.26% <100.00%> (+<0.01%)	⬆️
notifications_app	97.40% <ø> (ø)
notifications_push_repository	98.59% <ø> (ø)
sort_box	90.90% <ø> (ø)		Carriedforward from 049c925
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
...xtcloud/lib/src/api/webdav/models/webdav_file.dart	100.00% <100.00%> (ø)
...account_repository/lib/src/models/credentials.dart	94.73% <50.00%> (-5.27%)	⬇️

[Leptopoda]

LGTM but still missing some unit tests

[provokateurin]

I didn't add tests for everything given that I will remove most of them in #2561, so I only added tests for what will stay.