fix(x/ecocredit): don't allow self transfer in MsgSend

[aleem1314]

Description

Ref: #1660

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Author Checklist

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please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[codecov]

Codecov Report

Merging #1674 (aa58c17) into main (605edb1) will decrease coverage by 0.01%.
The diff coverage is 50.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1674      +/-   ##
==========================================
- Coverage   73.07%   73.06%   -0.02%     
==========================================
  Files         228      228              
  Lines       13409    13415       +6     
==========================================
+ Hits         9799     9802       +3     
- Misses       2894     2896       +2     
- Partials      716      717       +1     

Impacted Files	Coverage Δ
x/ecocredit/base/keeper/msg_send.go	67.88% <0.00%> (-1.52%)	⬇️
x/ecocredit/base/types/v1/msg_send.go	95.45% <100.00%> (+0.33%)	⬆️