refactor(x/ecocredit): remove duplicate pagination nil check

[aleem1314]

Description

Ref: #1456

Removes duplicate pagination nil check for AllBalances query method.

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[aleem1314]

This is a duplicate check. GogoPageReqToPulsarPageReq handles nil check.

[ryanchristo]

tACK. Updated title to be more descriptive. Also note chore should only be used when not updating production code.