Add support for adding ACC descriptive text to a component

Feature Request Description

Give the developers the possibility to add accessible description text in ui5-webcomponents. For this we need to test possible approaches and extend/reuse the existing AriaLabelHelper util.

Proposed Solution

Similar to the accessibleName and accessibleNameRef, one should be able to add accessible description via an attribute (accessibleDescription/accessibleDescriptionRef). After the merge of #6364 we should extend the logic of the AriaLabelHelper (or re-use it) to cover this functionality. It could be achieved in two ways:

• an accessibleDescription/accessibleDescriptionRef is passed to a web component. The value of the property/the text content of the element (should be handled in the same way as the accessibleNameRef) is passed to the aria-description attribute in the shadowDOM. This should be carefully tested as the aria-description property is still in draft https://w3c.github.io/aria/#aria-description. We should test on JAWS 2023, VoiceOver and NVDA latest and Chrome, Firefox, Edge & Safari. Check the current support stated here: https://developer.mozilla.org/en-US/docs/Web/API/Element/ariaDescription. If this does not work correctly in the tested SR+Browser combination we should focus on the second approach.
• an accessibleDescription/accessibleDescriptionRef is passed to a web component. The value of the property/the text content of the element (should be handled in the same way as the accessibleNameRef) is passed as a textContent to a hidden span which is placed in the same shadow DOM as the element with the respective role (the one that receives the focus). This element should have an aria-describedby attribute pointing to the hidden span.

Additional Context

• Regardless of the approach if an accessibleDescriptionRef is used it should also reflect dynamic changes of descriptive element. Example:
  <span id="descriptive-text">Element Description</span> <ui5-combobox accessible-description-ref="descriptive-text"></ui5-combobox> .... document.getElementById("descriptive-text").innerHTML = "New Description"
  -here the accessible description in the shadow DOM should be updated to New Description as well.
• Depending on the use case component developers should decide if they want to enable the accessibleDescription, the accessibleDescriptionRef or both.
• Please be aware that the aria-describedby is not announced for some roles. More info could be found in the aria specification (example - https://www.w3.org/WAI/tutorials/tables/caption-summary/#using-aria-describedby-to-provide-a-table-summary)

Priority

• Low
• Medium
• High
• Very High

A clear and concise description of the impact/urgency of the required feature.

Related Issues

Notice that the feature is requested several times:

• - ui5-input: #5607
• - ui5-table: #6432
• - ui5-tree: #5593
• - ui5-button: #5310 https://github.com/UI5/webcomponents/issues/6445
• - ui5-link: #3993 https://github.com/UI5/webcomponents/issues/6445
• - ui5-list: #6181

All of them should be evaluated again (before enabling them), since in most cases the better approach is to label the element and to not add a description to it. Nevertheless the aria-describedby is not announced for certain roles and each case should be tested separately.

Please link other issues related to this if some component is missing.

Expected result

• The AriaLabelHelper should be extended to cover accessible description scenario or a new util should be created.
• We should evaluate if we should use aria-description or aria-describedby internally
• After this issue is resolved feature requests for accessible description for every component should be enabled and evaluated separately