[Issue] Introduce separate BlockByIdentifier class to get Layout Block based on CMS Block Identifier

This issue is automatically created based on existing pull request: #28147: Introduce separate BlockByIdentifier class to get Layout Block based on CMS Block Identifier

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Preconditions: (*)

The existing class is anti-pattern:

1. Uses \Magento\Framework\Model\AbstractModel::load to load Model
2. If block_id is identifier, the getIdentities method returns same identity whatever the Scope is (return [\Magento\Cms\Model\Block::CACHE_TAG . '_' . $this->getBlockId()];), which is painful when you use the same identifier for multiple per-store CMS blocks.

Why can't we fix the original Block? Some of developers might have used:

        <referenceContainer name="page.top">
            <block class="Magento\Cms\Block\Block" name="header.info" after="navigation.sections">
                <arguments>
                    <argument name="block_id" xsi:type="string">666</argument>
                </arguments>
            </block>
        </referenceContainer>

That is why we keep old Block backwards-compatible and introducing new one that can be used explicitly:

        <referenceContainer name="page.top">
            <block class="Magento\Cms\Block\BlockByIdentifier" name="header.info" after="navigation.sections">
                <arguments>
                    <argument name="identifier" xsi:type="string">header-info</argument>
                </arguments>
            </block>
        </referenceContainer>

Related Pull Requests

Fixed Issues (if relevant)

1. magento/magento2#<issue_number>: Issue title

Steps to reproduce (*)

Actual Result (*)

Expected Result (*)

1. ...
2. ...

Questions or comments

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 are green)

[magento-engcom-team]

✅ Confirmed by @engcom-Alfa
Thank you for verifying the issue. Based on the provided information internal tickets MC-36814 were created

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