Configurable: remove unused double foreach loop

[Hanmac]

Description (*)

The double foreach does nothing of value inside the Block:

• it just calls $this->_preparePrice which just does format the price value.
• but then it does nothing with it. Even where it supposed to go inside $_prices variable hasn't been working for 16 years since Magento 1.1 when this file was created.
• In theory, the variables aren't even used and could be removed too. But that might be more of a BC break.

Related Pull Requests

Fixed Issues (if relevant)

1. Fixes OpenMage/magento-lts#2246

Manual testing scenarios (*)

1. ...
2. ...

Questions or comments

Contribution checklist (*)

• [x] Pull request has a meaningful description of its purpose
• [x] All commits are accompanied by meaningful commit messages
• [x] All automated tests passed successfully (all builds are green)
• [x] Add yourself to contributors list

[fballiano]

after reading the code I did a few tests and couldn't see any problem