Add invoice currency check with chain network

[chenyukang]

Closes #221

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 20 lines in your changes missing coverage. Please review.

Project coverage is 44.39%. Comparing base (a18a73b) to head (87192a8).

Files with missing lines	Patch %	Lines
src/rpc/invoice.rs	0.00%	20 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #273      +/-   ##
==========================================
- Coverage   44.42%   44.39%   -0.03%     
==========================================
  Files          44       44              
  Lines       28095    28112      +17     
==========================================
  Hits        12480    12480              
- Misses      15615    15632      +17     

Flag	Coverage Δ
unittests	44.39% <0.00%> (-0.03%)	⬇️

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