fix: priority not working for multiple pricing rules (backport #41516)

[mergify]

Issue

• Create a Pricing Rule for item code, keep priority as blank and set the discount percentage as 10
• Create another Pricing Rule item group, keep priority as 2 and set the discount percentage as 20
• System will apply the first pricing rule and not second

Problem

Here if the apply multiple pricing rules has not enabled then system not consider the pricing rules set on the Item Group and Brand.

Solution

To fix the issue, added the "Has Priority" checkbox to know whether the Priority has to be consider or not

---

This is an automatic backport of pull request #41516 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 5cf5b18 has failed:

On branch mergify/bp/version-14-hotfix/pr-41516
Your branch is up to date with 'origin/version-14-hotfix'.

You are currently cherry-picking commit 5cf5b18aea.
  (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/pricing_rule/test_pricing_rule.py
	modified:   erpnext/accounts/doctype/pricing_rule/utils.py
	new file:   erpnext/patches/v14_0/enable_set_priority_for_pricing_rules.py

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

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

[frappe-pr-bot]

🎉 This PR is included in version 14.70.1 🎉

The release is available on GitHub release

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