fix: reject nft-transfer sends on non-nft port

[songgaoye]

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[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 34.84%. Comparing base (f8a53d8) to head (c9dae84).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
x/nft-transfer/keeper/relay.go	0.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1252      +/-   ##
==========================================
+ Coverage   33.50%   34.84%   +1.34%     
==========================================
  Files         105      113       +8     
  Lines       15728    15995     +267     
==========================================
+ Hits         5270     5574     +304     
+ Misses       9415     9377      -38     
- Partials     1043     1044       +1     

Flag	Coverage Δ
integration_tests	26.01% <0.00%> (-0.01%)	⬇️
integration_tests_byzantine	11.51% <0.00%> (-0.01%)	⬇️
integration_tests_gov	11.75% <0.00%> (-0.01%)	⬇️
integration_tests_grpc	11.75% <0.00%> (-0.01%)	⬇️
integration_tests_ibc	26.76% <33.33%> (+<0.01%)	⬆️
integration_tests_ledger	11.74% <0.00%> (-0.01%)	⬇️
integration_tests_slow	11.74% <0.00%> (-0.01%)	⬇️
integration_tests_solomachine	11.55% <0.00%> (-0.01%)	⬇️
integration_tests_upgrade	11.75% <0.00%> (-0.01%)	⬇️
unit_tests	8.72% <33.33%> (?)

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