chore(erc20): revert unnecessary logic on genesis

[GAtom22]

Description

This PR removes unnecessary logic from the genesis of the erc20 module.

This logic should not include the deployment of the corresponding erc20 contracts for the token pairs, but these should be included on the genesis of the evm module.

For reference on how this would look like, check the osmosis-outpost.jsonnet file

---

Closes #XXX

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (51cc816) 70.48% compared to head (ae13493) 70.43%.
Report is 1 commits behind head on main.

❗ Current head ae13493 differs from pull request most recent head 46bb04a. Consider uploading reports for the commit 46bb04a to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2292      +/-   ##
==========================================
- Coverage   70.48%   70.43%   -0.05%     
==========================================
  Files         294      293       -1     
  Lines       22640    22539     -101     
==========================================
- Hits        15957    15875      -82     
+ Misses       5814     5801      -13     
+ Partials      869      863       -6     

Files	Coverage Δ
x/erc20/genesis.go	72.22% <100.00%> (+22.22%)	⬆️
x/erc20/keeper/evm.go	88.23% <93.75%> (+3.05%)	⬆️

[Vvaradinov]

LGTM!