fix: Robustly parse file action responses and handle tooltip/URL children

[Rello]

Motivation

• Support server responses that wrap payload in the ocs.data envelope and use tooltip for success messages.
• Avoid failing when the root element is absent or when child elements are incomplete.
• Correctly resolve relative child url values against _accountUrl and improve logging for unsupported response elements.

Description

• Added #include <optional> and updated FileActionsModel::processRequest to extract ocs.data and the tooltip string from the JSON response.
• Use a fallback to ocs.data.root when top-level root is empty and prefer tooltip over the generic success message when present.
• Introduced setGenericResponse and parseChildResponse lambdas; parseChildResponse returns a std::optional<Response> and validates element, text, and url fields and resolves relative URLs against _accountUrl.
• Improved handling of child rows by using parsed responses when available, logging unsupported elements, and falling back to a generic response when parsing fails.

Testing

• Built the project with cmake and the changes compiled without errors.
• Ran the automated test suite with ctest, and all tests completed successfully.

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Codex Task

[Rello]

Responses are parsed correctly

Return URL from client integration with URL type:

Message from client integration, that is sending a tooltip:

[github-actions]

Artifact containing the AppImage: nextcloud-appimage-pr-9547.zip

Digest: sha256:c9a943906f79820c91bae2c9967cb1b228efa7bc91043e6d631607e2cd57dd78

To test this change/fix you can download the above artifact file, unzip it, and run it.

Please make sure to quit your existing Nextcloud app and backup your data.

[sonarqubecloud]

Quality Gate failed

Failed conditions
25.5% Coverage on New Code (required ≥ 80%)
B Maintainability Rating on New Code (required ≥ A)
13 New Code Smells (required ≤ 0)

See analysis details on SonarQube Cloud

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