Fix accepted types for escaper methods

[hostep]

Description (*)

When performing static analysis using phpstan on level 5 or higher on (custom) phtml files, we often run into false positives that have to do with the kind of data we send to one of the many escape methods.
Also the return type of escapeHtml was not clear as it can return a string or array depending on the type you send to the method.

We fix that in this PR.

Many thanks to @navarr who came up this suggested solution in scope of bitExpert/phpstan-magento#346

Related Pull Requests

Fixed Issues (if relevant)

1. Fixes Unclear/invalid return types in Magento\Framework\Escaper #40012

Manual testing scenarios (*)

See #40012 & bitExpert/phpstan-magento#346
Maybe I'll find more time later to work out a good example, but I don't have the time at the moment.

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)
• README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• All automated tests passed successfully (all builds are green)

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[hostep]

@magento run all tests