fix: fix gentx parser into the cosmosutil package (backport #4402)

[mergify]

Fix gentx parser into the cosmosutil package because the use of Delegator Address in MsgCreateValidator is deprecated

https://github.com/cosmos/cosmos-sdk/blob/8bfcf554275c1efbb42666cc8510d2da139b67fa/proto/cosmos/staking/v1beta1/tx.proto#L66-L69

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This is an automatic backport of pull request #4402 done by Mergify.

[mergify]

Cherry-pick of bf2539d has failed:

On branch mergify/bp/release/v28.x.y/pr-4402
Your branch is up to date with 'origin/release/v28.x.y'.

You are currently cherry-picking commit bf2539d6.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   changelog.md
	modified:   ignite/pkg/cosmosutil/gentx_test.go
	modified:   ignite/pkg/cosmosutil/testdata/gentx2.json

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   ignite/pkg/cosmosutil/gentx.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[julienrbrt]

The original PR shouldn't have been merged because require tests were failing.