[EVM] Add erc20 to cw20 pointer tests

[stevenlanders]

Describe your changes and provide context

• makes --value an optional parameter for registering a cw20 pointer
• adds new erc20->cw20 pointer tests

Testing performed to validate your change

• new integration test

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.18%. Comparing base (14ce997) to head (15219aa).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1593   +/-   ##
=======================================
  Coverage   61.18%   61.18%           
=======================================
  Files         366      366           
  Lines       26079    26079           
=======================================
  Hits        15957    15957           
  Misses       9116     9116           
  Partials     1006     1006           

see 2 files with indirect coverage changes