fix: deduplicate gain/loss JE creation for journals as payment (backport #36911)

[mergify]

This is an automatic backport of pull request #36911 done by Mergify.
Cherry-pick of 79c6f01 has failed:

On branch mergify/bp/version-14-hotfix/pr-36911
Your branch is up to date with 'origin/version-14-hotfix'.

You are currently cherry-picking commit 79c6f0165b.
  (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:   erpnext/accounts/utils.py

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   erpnext/controllers/accounts_controller.py

Cherry-pick of d6a3b9a has failed:

On branch mergify/bp/version-14-hotfix/pr-36911
Your branch is ahead of 'origin/version-14-hotfix' by 3 commits.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit d6a3b9a5c7.
  (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:   erpnext/accounts/doctype/payment_reconciliation_allocation/payment_reconciliation_allocation.json
	modified:   erpnext/accounts/doctype/payment_reconciliation_payment/payment_reconciliation_payment.json
	modified:   erpnext/accounts/utils.py
	modified:   erpnext/controllers/accounts_controller.py

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   erpnext/accounts/doctype/payment_reconciliation/payment_reconciliation.py

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

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[frappe-pr-bot]

🎉 This PR is included in version 14.38.0 🎉

The release is available on GitHub release

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