fix: cost center & account validation in Sales/Purchase Taxes and Charges

[Anuja-pawar]

Issue: Currently, there is no validation for the cost center in the Sales/Purchase Taxes and Charges Template, which further causes issues while creating purchase/sales invoices.

Steps to replicate:

1. Create Sales/Purchase Taxes and Charges Template
2. Change the Company in that form after entering the values in the taxes table
3. Create Sales/Purchase Invoice and include that tax template

You would get an error as shown below even though you select the correct cost center in Sales/Purchase Invoice and its item table

because the wrong cost center is fetched in the taxes table.

[nextchamp-saqib]

@Anuja-pawar There's a bunch of failing tests since the validation is working. You will have to fix them now. 😅

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed within a week if no further activity occurs, but it only takes a comment to keep a contribution alive :) Also, even if it is closed, you can always reopen the PR when you're ready. Thank you for contributing.

[coveralls]

Coverage increased (+0.05%) to 42.756% when pulling 97372fd on Anuja-pawar:fix-cost-center-validation into 7ba8c82 on frappe:develop.