fix: propagate missing chunk error

[appcypher]

Summary

As it is, the file content streaming implementation can panic if there is a missing chunk.
We should avoid unwrap as much as possible in the code and allow user to handle errors. This PR fixes that with the try_stream_ext

Test plan (required)

scripts/rs-wnfs.sh test

Closing issues

Fixes #228

[codecov]

Codecov Report

Merging #252 (7652f67) into main (bccc0ec) will increase coverage by 0.05%.
The diff coverage is 83.33%.

@@            Coverage Diff             @@
##             main     #252      +/-   ##
==========================================
+ Coverage   61.72%   61.77%   +0.05%     
==========================================
  Files          35       35              
  Lines        2662     2676      +14     
  Branches      655      657       +2     
==========================================
+ Hits         1643     1653      +10     
- Misses        566      567       +1     
- Partials      453      456       +3     

Impacted Files	Coverage Δ
wnfs/src/private/file.rs	79.92% <80.00%> (-0.15%)	⬇️
wnfs/src/private/directory.rs	71.39% <100.00%> (ø)

... and 4 files with indirect coverage changes

[matheus23]

Aw nice. The negative test is

Just needs newer clippy to be made happy.