feat: change pob to block-sdk

[beer-1]

• Create new tx service to address the below issue
  bug: passing proposal info as first txs make /cosmos/tx/v1beta1/txs/block/ query failed  skip-mev/block-sdk#215

This is following PR of #11

[Vritra4]

LGTM

[codecov]

Codecov Report

Merging #18 (0ece600) into main (c06ada3) will increase coverage by 0.12%.
The diff coverage is 88.50%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #18      +/-   ##
==========================================
+ Coverage   44.31%   44.44%   +0.12%     
==========================================
  Files         165      164       -1     
  Lines       16046    16075      +29     
==========================================
+ Hits         7111     7144      +33     
+ Misses       8156     8152       -4     
  Partials      779      779              

Files	Coverage Δ
app/genesis.go	43.43% <100.00%> (ø)
app/app.go	88.50% <94.66%> (+0.20%)	⬆️
app/export.go	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes