Fix module uninstall shell command and composer removal w/out regression

[Thundar]

Description

There is a discrepancy between composer.lock and composer.json when removing a module via bin/magento module:uninstall command. Also, the output is wrong and the guide says it should do otherwise.
The removal option in the code solved the previous issue #5797 , but caused the new issue. The new change solves both.

Fixed Issues (if relevant)

1. Module uninstall does not work with composer #17780: Module uninstall does not work with composer

Manual testing scenarios

1. Install Magento with composer (2.2.x) and set it up
2. Install Sample Datas with bin/magento sampledata:deploy
3. Complete Sample Data installation: bin/magento setup:upgrade
4. Remove one package: bin/magento module:uninstall Magento_CmsSampleData

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @Thundar. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
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[magento-engcom-team]

@Thundar thank you for contributing. Please accept Community Contributors team invitation here to gain extended permissions for this repository.

[magento-engcom-team]

Hi @Thundar. Thank you for your contribution.
We will aim to release these changes as part of 2.2.8.
Please check the release notes for final confirmation.

Please, consider to port this solution to 2.3 release line.
You may use Porting tool to port commits automatically.

[magento-engcom-team]

Hi @Thundar. Thank you for your contribution.
We will aim to release these changes as part of 2.2.8.
Please check the release notes for final confirmation.

Please, consider to port this solution to 2.3 release line.
You may use Porting tool to port commits automatically.