Accessibility in the statistics table

[Andrea-Guevara]

References

• Fixes #3300

Description

Creation of a method that conditionally defines a dynamic label for the object column.

Instructions for Reviewers

List of changes in this PR:

• The “getObjectHeaderLabel” method has been created to conditionally set a label to the column of objects.
• To differentiate between the label and the content, the two labels have been defined in the html using “<th scope=”col">" and the "td" tag has been used for the content.
• New translation keys have been added in english, portuguese and spanish.

Include guidance for how to test or review your PR.

1. Go to the statistics area and see that the table now has a label for each column.

Checklist

• [ ] My PR is created against the main branch of code (unless it is a backport or is fixing an issue specific to an older branch).
• [ ] My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• [ ] My PR passes ESLint validation using npm run lint
• [ ] My PR doesn't introduce circular dependencies (verified via npm run check-circ-deps)
• [ ] My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• [ ] My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• [ ] My PR aligns with Accessibility guidelines if it makes changes to the user interface.
• [ ] My PR uses i18n (internationalization) keys instead of hardcoded English text, to allow for translations.
• [ ] My PR includes details on how to test it. I've provided clear instructions to reviewers on how to successfully test this fix or feature.
• [ ] If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• [ ] If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• [ ] If my PR fixes an issue ticket, I've linked them together.