Fix incorrect translation key for parameter_not_allowed.detail

[pozzer]

Closes https://github.com/cerebris/jsonapi-resources/issues/1468.

All Submissions:

• I've checked to ensure there aren't other open Pull Requests for the same update/change.
• I've submitted a ticket for my issue if one did not already exist.
• My submission passes all tests. (I ran the full test suite locally to avoid unnecessary failures.)
• I've used Github auto-closing keywords in the commit message or the description.
• I've added/updated tests for this change.

Bug fixes and Changes to Core Features:

• I've included an explanation of what the changes do and why I'd like you to include them.
• I've provided test(s) that fail without the change.

Test Plan:

The issue occurs because the translation key being used in the code is incorrect.
The code currently looks for parameters_not_allowed.detail (plural), but the correct key in the translation files is parameter_not_allowed.detail (singular).

• Added a test to verify that the correct key (parameter_not_allowed.detail) is used.
• Without the fix, the test fails because the translation isn't found, falling back to the default English message.
• With the fix, the test correctly retrieves the translation.

Reviewer Checklist:

• Maintains compliance with JSON:API
• Adequate test coverage exists to prevent regressions